Summary
In April 1982, the partial remains of an unidentified homicide victim were found in an almond orchard in Manteca, California, which is in San Joaquin County. The San Joaquin County Sheriff's Office responded and began collecting evidence and investigating. It was determined that the victim was a White man who appeared to be about 22 to 26 years old and had distinctive tattoos including a snake's head in blue ink on the outside of his right wrist and a colored grim reaper tattoo on his left forearm.
Despite a lengthy investigation and extensive community outreach, including releasing photos of the man's tattoos, he could not be identified and became known as Manteca John Doe. Details of the case were entered into the National Missing and Unidentified Persons System (NamUs) as UP68492. 
In 2024, the San Joaquin County Sheriff's Office submitted forensic evidence to Othram in The Woodlands, Texas to determine if advanced DNA testing could help identify the victim. Othram scientists successfully developed a DNA extract from the provided evidence and then used Forensic-Grade Genome Sequencing® to build a comprehensive DNA profile for the victim. The DNA profile was returned to the San Joaquin County Sheriff's Office who worked with the FBI's forensic genetic genealogy team to develop new leads in the case.
Using this new information, a follow-up investigation was conducted leading investigators to potential relatives of the victim. Reference DNA samples were collected from a relative and compared to the DNA profile of the unidentified man. This investigation led to the positive identification of the man, who is now known to be Danny Joe Jentzen, from Flint, Michigan, born July 8, 1954. At the time his remains were found, he would have been 27 years old.
Jentzen's family said he grew up as a ward of the state, had some law enforcement contact in Southern California and San Francisco, and may have struggled with mental health challenges, according to the Sheriff's Office. His sister last saw him as a child after their father and younger brother were killed in a tragic car accident.
The investigation into Jentzen's homicide continues and the San Joaquin Sheriff's Office is asking that anyone with information about Danny Joe Jentzen or the circumstances surrounding his disappearance and death should please contact the San Joaquin County Sheriff's Office at (209) 468-4400.
If you would like to support efforts to solve more cases like this, consider contributing your DNA data to the DNASolves database which aids law enforcement in identifying suspects and giving families the answers they deserve.
The identification of Danny Jentzen represents the 69th case in the State of California where officials have publicly identified an individual using technology developed by Othram. Visit DNASolves to learn about other California cases where your support can help bring long-awaited answers to families.
Dan Miller
Director of Customer Service
Dan guides law enforcement agencies across the United States and internationally through every step of the forensic process—from crime scene to courtroom. He ensures investigators have the support and resources they need to navigate advanced DNA testing and maximize the impact of forensic evidence in their cases.