Skip to the content

The Pyramid1 case2 readings

The Pyramid, explained: each tier removes a way to get caught

Five tiers, sorted by how many ways there are to catch a killer. Each step up removes one.

The short answer

What is the pyramid, and what does it rank?

The pyramid is this site’s own analytical model, not an FBI typology. It ranks five kinds of serial killer by how many ways exist to catch them, and each step up removes one. The FBI’s 2008 monograph on serial murder reports that its experts agreed there is no generic profile of a serial murderer.123

Pyramid · The Pyramid

Each step up removes one way to get caught

  1. Tier 1 · stranger, no identifying trace, stopsZodiac, open case: nothing left to catchSource: Leah Asmelash and Cheri Mossburg, ‘After 51 years, the Zodiac Killer’s cipher has been solved by amateur codebreakers’ (CNN, Dec. 11, 2020): five unsolved murders between 1968 and 1969; the offender never caught; the FBI statement of Dec. 11, 2020
  2. Tier 2 · the plannerKeyes, confessed, died before trial: caught by one mistakeSource: FBI Houston, ‘Serial Killer Spent Time in Texas’ (press release, Aug. 13, 2013), FBI archives, archived copy: arrest of Mar. 13, 2012 in Lufkin, Texas, for access device fraud tied to Samantha Koenig’s ATM card; death in custody in Anchorage on Dec. 2, 2012, after confessing
  3. Tier 3 · unreported victimsRidgway: caught by DNA, lateSource: Seattle Times staff, ‘Timeline of the Green River killer case’ (The Seattle Times, Feb. 18, 2011): the police contacts of 1983, 1984 and 1987; DNA testing from March 2001; the arrest; the plea of Nov. 5, 2003; Rebecca Marrero’s dates and the 2011 plea
  4. Tier 4 · organized, stable lifeRader: caught by biology / egoSource: Federal Bureau of Investigation, Behavioral Analysis Unit-2, National Center for the Analysis of Violent Crime, ‘Serial Murder: Multi-Disciplinary Perspectives for Investigators’ (FBI, 2008; report of the symposium of August 29 to September 2, 2005), archived copy of the FBI.gov page ‘Serial Murder’: no generic profile of a serial murderer; broad, non-inclusive categories of motivation; most typologies too cumbersome for an active investigation; serial murderers who often have families, homes and jobs; very few who travel interstate; the myth that serial killers cannot stop, with Dennis Rader and Jeffrey Gorton as its examples; Rader’s ten victims, 1974 to 1991, his family, job and church office, his 2004 return and the disk
  5. Tier 5 · falls apartDahmer: caught by behaviorSource: Estate of Sinthasomphone v. City of Milwaukee, 785 F. Supp. 1343 (E.D. Wis. Mar. 5, 1992), decision and order of Chief Judge Terence T. Evans (Harvard Law School Library, Caselaw Access Project): 17 killings confessed; the guilty pleas in Milwaukee County; the police response of May 27, 1991; the five victims it names from May to July 1991; the escape and the arrest of July 22, 1991; the Ohio charge for the 1978 killing of Steven Hicks
  • Event
  • Open case
Notation
The line
Time, left to right. Down the screen on a phone.
Event
A fact on the record.
Missed chance
The system had him and let him go.
The catch
The error that ended it, knocked out of line.
Open case
No one charged.
A wait
Time passes and nothing moves.
Data table
Each step up removes one way to get caught
TierPatternExampleStatusCaught by
5falls apartDahmerConvictedcaught by behavior
4organized, stable lifeRaderConvictedcaught by biology / ego
3unreported victimsRidgwayConvictedcaught by DNA, late
2the plannerKeyesconfessed, died before trialcaught by one mistake
1stranger, no identifying trace, stopsZodiacopen casenothing left to catch

Readings

2 in this series

  1. 01

    Hard to catch and needing to be caught are two different things

    Near Chicago, 33 young men and boys were murdered from 1972 to 1978 by a man police already knew. A Northern California case of five murders is still open.

  2. 02

    The top of the pyramid holds a short series: four attacks, no arrest

    Eight shootings in New York in 12 months ended in an arrest. Four attacks in Northern California in under 10 months did not, and the official count stops there.

The argument

The Pyramid

What is the pyramid, and what is it not?

The pyramid is this site’s own analytical model and has no official standing. It ranks five kinds of serial killer by one measure: how many ways exist to catch them. From the base up, each tier takes away one way to get caught, and at the top nothing is left to catch. The FBI’s 2008 monograph on serial murder works differently: it suggests broad categories of motivation as guidelines for investigation and calls most typologies too cumbersome to use during an active investigation.123

Tier 5 · caught by behavior

Tier 5: who is caught by his own behavior?

Tier 5 is for men who fall apart: the killings speed up, and the killer’s own conduct closes the case. The example is a Wisconsin case: between 1978 and 1991, 17 boys and young men were killed, the first of them Steven Hicks, 18, in Ohio.456 A federal court’s summary names five killed in the eight weeks before the arrest: Konerak Sinthasomphone, 14, Matt Turner, Jeremiah Weinberger, Oliver Lacy and Joseph Bradehoft.5

The court’s summary says Milwaukee police answered a call about Konerak Sinthasomphone on May 27, 1991 and determined that nothing was amiss, and that he was killed later that evening.5 On July 22, 1991, another man escaped and led police to Jeffrey Dahmer.457 He confessed to 17 killings over 13 years and was convicted of 16.457

In Wisconsin v. Dahmer (1992), he pleaded guilty but insane to 15 murders.89 A jury found him sane on February 15, 1992, and on February 17 a judge sentenced him to 15 consecutive life terms.6910 In Ohio he pleaded guilty to the murder of Steven Hicks and received a 16th life term on May 1, 1992.46

Tier 4 · caught by biological evidence or need for recognition

Tier 4: what catches an organized man with a stable life?

Tier 4 is for men who do not fall apart: they hold jobs and keep families. The FBI’s monograph says serial murderers often have families, homes and jobs, and that many hide in plain sight within their communities.1 What catches them is what they left at the scenes and what they choose to say.

The example is a Kansas case: between 1974 and 1991, 10 people were murdered in and around Wichita.111 The first, on January 15, 1974, were Joseph and Julie Otero and their 11- and 9-year-old children.11121314 The FBI says Dennis Rader was married with two children, worked as a local government official and was president of his church.111

The FBI says he killed no one after 1991.1 In 2004 he began writing to the media again.113 A computer disk he sent was traced to his church and identified him, and DNA testing confirmed it.1111214 He was arrested on February 25, 2005.1314

In Kansas v. Rader (2005), he pleaded guilty in June to 10 counts of first-degree murder.11141516 On August 18, 2005, he was sentenced to 10 consecutive life terms.1517 The case ran 31 years.1214

Tier 3 · caught by DNA, late

Tier 3: why does it take so long when nobody reports the victims?

Tier 3 is for killers whose victims the system is slow to look for, so no report starts the clock. The example is a Washington case: 49 women and girls killed in King County, almost all of them between 1982 and 1984.181920 Rebecca Marrero, 20, was last seen on December 3, 1982.2021 She was not reported missing until July 20, 1984.2021

Gary Ridgway claimed that one reason he picked these women was that he believed police would not look as hard for them if they went missing, prosecutors recorded.22 They wrote that his assessment was correct: police were often delayed because no missing person report was filed.22

He came to police attention in 1983 and passed a polygraph in 1984.2022 In April 1987 police searched his home and took a saliva sample.192022 In March 2001 a state crime lab began DNA testing of the evidence, and he was arrested on November 30, 2001.192022

In State v. Ridgway, he pleaded guilty on November 5, 2003 to 48 counts of aggravated first-degree murder and was sentenced to life without parole.181920 In 2011 he pleaded guilty to a 49th murder, Rebecca Marrero’s.1820 It took 19 years from the first body found in 1982 to his arrest.1920

Tier 2 · caught by one broken rule

Tier 2: what catches a planner?

Tier 2 is for the planner who travels, with no tie to his victims and no home territory. The FBI’s monograph says most serial killers have very defined geographic areas of operation, and very few travel interstate to kill.1

The example was never tried.23 Samantha Koenig, 18, was abducted on February 1, 2012 from the Anchorage coffee stand where she worked.2425 Bill and Lorraine Currier were murdered in Vermont in 2011.2425 Israel Keyes confessed to those murders and died before trial.232526

What follows is the FBI’s account, untested in court. The FBI believes he killed 11 people between 2001 and March 2012.2425 It says it was not unusual for him to fly into an airport, rent a car and drive hundreds of miles, and that investigators believe he knew none of his victims.232527

He buried caches of weapons and money around the country, the FBI says, so he did not have to risk credit cards that would tie him to a crime in one area.242527 One case broke both habits: Samantha Koenig was taken in Anchorage, the city where he lived.2528 On March 13, 2012, he was arrested in Lufkin, Texas, for access device fraud tied to her ATM card.2426 He died by suicide in custody in Anchorage on December 2, 2012, while awaiting trial.232426

Tier 1 · caught by nothing left to catch

Tier 1: which case has nothing left to catch?

By this model the hardest case is a stranger who leaves nothing that names him and stops. The example is an open case in Northern California: five people murdered in the San Francisco Bay Area in 1968 and 1969, by an offender who has never been identified.293031

Tier 1 removes the last two things: a trace that names the offender, and a next attempt. The example is an open case in Northern California, known in the press as the Zodiac case: no one has been identified, and it has no legal outcome.293032

Betty Lou Jensen, David Faraday, Darlene Ferrin, Cecelia Shepard and Paul Stine were murdered in the San Francisco Bay Area in 1968 and 1969.2930313334 Those five murders are the case’s official count.3032 In December 2020 the FBI’s San Francisco office said the case remains an ongoing investigation for the FBI and its local law enforcement partners.3132

What does the pyramid leave out?

The pyramid rests on five cases, and only three ended in convictions. It measures how hard a case is to close, not how many people died. It has no tier for a killer inside a trusted institution, such as Harold Shipman, a doctor convicted of murdering 15 of his patients.35

The pyramid rests on five cases: three ended in convictions, one in a confession that no court tested, and one is open.101720232632 That is a small base, and the order of the middle tiers depends on it. It measures how hard a case is to close, not how urgently a killer needed to be stopped, which has its own page.

It also leaves out killers who work inside a trusted institution. A public inquiry concluded that about 250 patients were killed by their own doctor between 1971 and 1998.36 The Inquiry records that the doctor, Harold Shipman, a general practitioner near Manchester, was convicted on January 31, 2000 of murdering 15 of his patients.35 No tier here describes that position.

The rule

Each step up, one catching mechanism disappears. At the top none are left. Only luck or a confession.

The cases

Filed under The Pyramid

Questions

Is the pyramid an FBI classification?

No. The pyramid is this site’s own analytical model. The FBI’s 2008 monograph on serial murder reports that its experts agreed there is no generic profile of a serial murderer, and it calls most typologies too cumbersome to use during an active investigation.123 The pyramid ranks cases by how many ways exist to catch the offender.

Which kind of serial killer is hardest to catch?

By the pyramid model, a stranger who leaves nothing that names him and stops. The one example is an open case in Northern California: five people murdered in 1968 and 1969, and an offender who has never been identified.293031

Do serial killers ever stop on their own?

Yes. The FBI lists the belief that serial killers cannot stop killing as a myth and says some stop altogether before being caught. One of its examples is Dennis Rader, who murdered 10 people from 1974 to 1991 and killed no one else before his capture in 2005.115

Why does the pyramid label Israel Keyes as confessed, died before trial?

No court tested the confessions of Israel Keyes, who confessed and died before trial. The FBI says he was arrested in Texas on March 13, 2012 and died by suicide in custody in Anchorage on December 2, 2012, while awaiting trial for the murder of Samantha Koenig.2326

Where does a killer like Harold Shipman fit on the pyramid?

Harold Shipman does not fit on the pyramid. The Shipman Inquiry records that he was a general practitioner convicted on January 31, 2000 of murdering 15 of his patients, and it concluded that he killed about 250.3536 Every tier assumes a killer outside the system. None describes one the system trusts.

The record

The Pyramid

Sources

  1. Federal Bureau of Investigation, Behavioral Analysis Unit-2, National Center for the Analysis of Violent Crime, ‘Serial Murder: Multi-Disciplinary Perspectives for Investigators’ (FBI, 2008; report of the symposium of August 29 to September 2, 2005), archived copy of the FBI.gov page ‘Serial Murder’: no generic profile of a serial murderer; broad, non-inclusive categories of motivation; most typologies too cumbersome for an active investigation; serial murderers who often have families, homes and jobs; very few who travel interstate; the myth that serial killers cannot stop, with Dennis Rader and Jeffrey Gorton as its examples; Rader’s ten victims, 1974 to 1991, his family, job and church office, his 2004 return and the disk

  2. Federal Bureau of Investigation, ‘Serial Murder - July 2008’ (FBI.gov documents page for the monograph’s PDF), archived copy of Mar. 31, 2025: the monograph’s publication date

  3. U.S. Department of Justice, Office of Justice Programs, National Criminal Justice Reference Service, library record NCJ 223848, ‘Serial Murder: Multi-Disciplinary Perspectives for Investigators’ (editor Robert J. Morton): date published 2008

  4. ‘Jeffrey Dahmer’ (Encyclopaedia Britannica, online entry), archived copy of June 29, 2026: 17 boys and young men killed, 1978 to 1991; the first murder in Bath Township, Ohio, in 1978; the escape of July 1991; 16 life sentences in 1992, the 16th added in May

  5. Estate of Sinthasomphone v. City of Milwaukee, 785 F. Supp. 1343 (E.D. Wis. Mar. 5, 1992), decision and order of Chief Judge Terence T. Evans (Harvard Law School Library, Caselaw Access Project): 17 killings confessed; the guilty pleas in Milwaukee County; the police response of May 27, 1991; the five victims it names from May to July 1991; the escape and the arrest of July 22, 1991; the Ohio charge for the 1978 killing of Steven Hicks

  6. ‘Dahmer sentenced to life for Hicks murder’ (United Press International, May 1, 1992), UPI Archives, archived copy: the Ohio guilty plea and life sentence of May 1, 1992 for the murder of Steven Hicks, 18; the Wisconsin sentence of Feb. 17, 1992

  7. HISTORY.com Editors, ‘Jeffrey Dahmer murdered in prison’ (History.com, published Feb. 9, 2010; last updated May 27, 2025): arrest of July 22, 1991; 17 killings confessed over a 13-year period; the plea of guilty but insane

  8. ‘WI v. Dahmer (1992)’ (Court TV trial archive page, undated), archived copy of Dec. 3, 2025: the case name; the plea of guilty but insane

  9. Jerry Smith, ‘Jury finds Dahmer sane’ (United Press International, Feb. 15, 1992), UPI Archives, archived copy: the sanity verdict of Saturday, Feb. 15, 1992; the plea of guilty but insane to 15 murders

  10. ‘Dahmer sentenced to 15 consecutive life terms in prison’ (Deseret News, Feb. 17, 1992): the sentence of Monday, Feb. 17, 1992; the sanity verdict of the Saturday before

  11. Associated Press, ‘BTK killer waives trial, admits 10 slayings’ (NBC News, June 2005; the page carries the stamp June 26, 2005 and reports a plea entered on a Monday): 10 killings in the Wichita area, 1974 to 1991; the Oteros, Jan. 15, 1974; his job, marriage and church office; the diskette traced to his church; the guilty plea to 10 counts of first-degree murder

  12. CBS/AP, ‘Police: Scout Leader Is BTK Killer’ (CBS News, Feb. 27, 2005): DNA as the key to the case; a 31-year manhunt; the Oteros

  13. Jeffrey Lutz and Cale Chapman, ‘On This Day: Dennis Rader arrested 20 years ago, Feb. 25, 2005’ (KWCH 12 News, Wichita, Feb. 25, 2025): arrest of Feb. 25, 2005; the Otero murders of Jan. 15, 1974; the letters that began in March 2004

  14. Mark Hansen, ‘How the Cops Caught BTK’ (ABA Journal, May 1, 2006): the disk traced through a church computer; DNA confirmation; arrest of Feb. 25, 2005; the guilty plea of June 2005 to 10 counts; 31 years; the ages of the two Otero children

  15. ‘BTK sentenced to 10 life terms’ (CNN, Aug. 18, 2005): the sentence of 10 consecutive life terms; the June plea to 10 murders, 1974 to 1991; the case name Kansas v. Dennis Rader, in the page’s link to court documents

  16. CBS/AP, ‘BTK Serial Killer Pleads Guilty’ (CBS News, June 27, 2005): the guilty plea to 10 counts on Monday, June 27, 2005

  17. Associated Press, ‘BTK killer gets maximum life sentence’ (NBC News, Aug. 18, 2005): the sentence of Thursday, Aug. 18, 2005, 10 consecutive life terms

  18. Lauren Girgis and Mike Carter (The Seattle Times), ‘Why the Green River killer was transferred to King County last year’ (Yakima Herald-Republic, Mar. 10, 2025): 49 known killings, almost all between 1982 and 1984; the 48 guilty pleas of 2003 and the 49th of 2011; life without parole

  19. David Wilma, ‘Gary Leon Ridgway pleads guilty to murdering 48 Green River Killer victims on November 5, 2003’ (HistoryLink.org Essay 4262, posted Nov. 5, 2003): the plea to 48 murders in King County; the case name, in its source list; the arrest of Nov. 30, 2001; life without parole; the 1987 sample; the first body found, July 15, 1982

  20. Seattle Times staff, ‘Timeline of the Green River killer case’ (The Seattle Times, Feb. 18, 2011): the police contacts of 1983, 1984 and 1987; DNA testing from March 2001; the arrest; the plea of Nov. 5, 2003; Rebecca Marrero’s dates and the 2011 plea

  21. ‘Skull found in Auburn ravine identified as possible victim of Green River Killer’ (Auburn Reporter, Dec. 23, 2010): Rebecca Marrero last seen Dec. 3, 1982 and reported missing July 20, 1984

  22. King County Prosecuting Attorney, ‘Prosecutor’s Summary of the Evidence’, State of Washington v. Gary Leon Ridgway, King County Superior Court No. 01-1-10270-9 SEA (undated filing that describes events through August 2003), copy hosted by The Seattle Times, archived Feb. 17, 2006: the police contacts of 1983, 1984 and 1987; the saliva sample; DNA testing from March 2001; the arrest of Nov. 30, 2001; his stated reason for choosing victims, paraphrased on the page; the prosecutors’ finding that the investigation was often delayed because no missing person report was filed

  23. FBI Portland, ‘FBI Asks for Help Identifying Potential First Victim of Serial Killer’ (press release, Dec. 7, 2012), FBI archives, archived copy: death in jail while awaiting trial; travel over great distances

  24. Federal Bureau of Investigation, ‘New Information Released in Serial Killer Case’ (FBI.gov story, Aug. 13, 2013), archived copy: Samantha Koenig, 18, abducted Feb. 1, 2012 from the Anchorage coffee stand where she worked; the Curriers, murdered in Vermont in 2011; the FBI’s belief in 11 victims, 2001 to March 2012; the caches and credit cards; arrest in Lufkin, Texas, Mar. 13, 2012; death on Dec. 2, 2012

  25. FBI Anchorage, ‘FBI Requests the Public’s Assistance in Case of Serial Killer Israel Keyes’ (press release, Aug. 12, 2013), FBI archives, archived copy: his admissions to the murders of Samantha Koenig and of Bill and Lorraine Currier; his residence in Anchorage; buried caches; no prior tie to his victims; 11 homicides believed, 2001 to March 2012. Israel Keyes confessed and died before trial; he was never tried.

  26. FBI Houston, ‘Serial Killer Spent Time in Texas’ (press release, Aug. 13, 2013), FBI archives, archived copy: arrest of Mar. 13, 2012 in Lufkin, Texas, for access device fraud tied to Samantha Koenig’s ATM card; death in custody in Anchorage on Dec. 2, 2012, after confessing

  27. FBI Anchorage, ‘FBI Requests the Public’s Assistance Concerning Israel Keyes’ (press release, Dec. 3, 2012), FBI archives, archived copy: his travel pattern; buried caches; no prior tie to his victims. Israel Keyes confessed and died before trial; he was never tried.

  28. U.S. Attorney’s Office, District of Alaska, ‘Anchorage Man Indicted for Kidnapping and Killing Samantha Koenig’ (press release, Apr. 18, 2012), as published on the FBI’s website, archived copy: Anchorage as his home city

  29. Federal Bureau of Investigation, ‘The Zodiac Killer’ (FBI.gov story, Mar. 2, 2007), FBI archives, archived copy: five murders in the Bay Area in 1968 and 1969; the offender’s identity unknown

  30. Michael Butterfield, ‘The Zodiac Killer: A Timeline’ (History.com, published Nov. 8, 2017; last updated May 28, 2025): the victims’ names; the official count of five murders; the offender never found

  31. Associated Press, ‘Zodiac cipher solved 51 years after it was sent to San Francisco Chronicle’ (as published by the Napa Valley Register, Dec. 11, 2020): the FBI San Francisco statement of Dec. 11, 2020; five killed in 1968 and 1969

  32. Leah Asmelash and Cheri Mossburg, ‘After 51 years, the Zodiac Killer’s cipher has been solved by amateur codebreakers’ (CNN, Dec. 11, 2020): five unsolved murders between 1968 and 1969; the offender never caught; the FBI statement of Dec. 11, 2020

  33. San Francisco State University, J. Paul Leonard Library, Bay Area Television Archive, ‘Double Murder of Faraday & Jensen (Zodiac)’, catalog record for KRON newsfilm 420-1, film date Dec. 21, 1968: the names Betty Lou Jensen and David Faraday

  34. Marsha Dorgan, ‘Online exclusive: In the wake, of the Zodiac’ (Napa Valley Register, Feb. 18, 2007): the spelling Cecelia Shepard

  35. The Shipman Inquiry, ‘Background to the Inquiry’ (official Inquiry website, Crown copyright), archived copy of Jan. 31, 2009: Harold Shipman’s conviction of Jan. 31, 2000 for the murder of 15 of his patients; his work as a general practitioner in Hyde, near Manchester

  36. The Shipman Inquiry, Sixth Report, Summary, ‘Conclusions’ (official Inquiry website, undated page), archived copy of Jan. 23, 2009: the Inquiry’s conclusion that Shipman killed about 250 patients between 1971 and 1998, 218 of them identified

Educational analysis. Adjudicated cases only. Victims named with respect.