After more than two decades, an Ohio man who died after being discovered unconscious on a Phoenix sidewalk has been identified.
Before his death, John Thiellesen’s brother reported him missing on September 1, 2004, according to a Facebook post from the Toledo Police Department in September 2023 as part of its “Still Missing” campaign.
The 42-year-old man, who had mental health issues, called his sister to say he was going to “cleanse” himself by jumping into the Maumee River, a large body of water that flows into Lake Erie.
It wasn’t until March 2025 that the circumstances surrounding his disappearance became clear.
The Maricopa County Office of the Medical Examiner in Arizona used investigative genetic genealogy to confirm that a John Doe who had been unidentified for more than 20 years was Thiellesen, according to Ramapo College of New Jersey, which collaborated on the investigation.
The medical examiner’s office, sheriff’s office, and Toledo Police Department did not immediately respond to PEOPLE’s inquiries for comment.
After making that call, Thiellesen was discovered alive but unconscious in Arizona. He was pronounced dead at a hospital on August 17, 2004, with no identification, according to the college. It’s unclear how he ended up in Phoenix.
At the time, the Phoenix Police Department attempted to identify the deceased man using fingerprints and DNA evidence, but was unsuccessful.
In 2024, the medical examiner’s office collaborated with the college’s Investigative Genetic Genealogy Center and two labs to help staff and students identify two of Thiellesen’s third cousins.
The medical examiner’s office and the Arizona Attorney General’s Cold Case Unit collaborated to obtain a DNA sample from one of his siblings, resulting in his successful identification.
Cairenn Binder, the Investigative Genetic Genealogy Center’s assistant director, tells PEOPLE that she is excited to collaborate with colleagues and students to answer long-standing questions for the families of missing people.
“There’s definitely satisfaction in providing those answers to family and closing the case once and for all,” she reflects.
However, there is a “element of sadness” to solving a cold case, according to Binder. “Of course, Mr. Thiellesen’s family would prefer to find him alive and well.”
