21-04-2025
'Hope for the loved ones': Investigators solve 20-year mystery of unidentified Phoenix man
On Aug. 17, 2004, a man died at St. Joseph's Hospital in Phoenix. While the death wasn't an unusual occurrence for the hospital, the way he was found was.
Just days earlier, he was lying unconscious on the sidewalk at Third Avenue and Madison Street. There was no identification on his person when emergency medical services took him to the hospital.
The identity would be a mystery for more than two decades.
That was until late December, when local authorities got the long-awaited breakthrough in the John Doe case they had been waiting on for years.
With the help of researchers at Ramapo College's Investigative Genetic Genealogy Center in Mahwah, New Jersey, local investigators confirmed that John Thielleson was their mystery man.
'This case showcases the power of investigative genetic genealogy to close longstanding missing persons cases,' Cairenn Binder, assistant director of the IGG Center, stated in a news release on April 16. 'Every John and Jane Doe is the answer to a family missing a loved one, and we will continue to do everything in our power to keep restoring their names and providing those answers.'
Back in 2004, the Phoenix Police Department worked to uncover Thielleson's identity. Officers ran fingerprints and entered DNA samples into the Combined DNA Index System, or CODIS.
They kept coming up empty.
Then in September 2024, the Maricopa County Office of the Medical Examiner reached out to Ramapo for help. After taking on the case, the genealogy center sent a portion of a bloodstain to a research organization called Genologue in Tucker, Georgia.
Genologue extracted DNA and determined the man's genetic material — a process called genome sequencing.
After Genologue's files were shared with Parabon Nanolabs, a DNA technology company, to analyze the biological data in November, undergraduate students in a Genealogy Center workshop course got to work to identify John Doe.
However, they were unable to finish the job before the semester ended, leaving the task to the Genealogy Center staff. Only a day into the school's winter break, the team found a pair of third cousins related to the man.
The team determined Thiellesen was the likely candidate and forwarded the info to Senior Medicolegal Death Investigator Christen Eggers of the Maricopa County Office of the Medical Examiner.
Working with the Arizona Attorney General's Cold Case Unit, the medical examiner positively confirmed Thiellesen's identity in March 2025.
'Ramapo College has become a beacon of hope for individuals and families across the nation,' Eggers stated. 'Their tireless efforts have provided answers to countless families and demonstrates an unyielding dedication to the welfare of all people, regardless of their circumstances.'
Arizona Attorney General Kris Mayes said she was proud of the Cold Case unit's work to help family members of missing and murdered Arizonans get closure.
'With increased technology, and the right kind of cooperative approach between law enforcement agencies,' she stated, 'there is hope for the loved ones of countless victims.'
If you have any information related to cases the Arizona Attorney General's Cold Case Unit is investigating or any other missing or murdered Arizonans, please submit your tip to the Cold Case Unit or visit Silent Witness.
This article originally appeared on Arizona Republic: John Doe unmasked: DNA helps solve case of man found dead in Phoenix
