DENVER (KDVR) — A man found near a river in Colorado in 1999 has been identified 23 years later, and authorities hope his loved ones can find closure.

The Denver Office of the Medical Examiner reports that it has averaged around one unidentified person per year since 1980, and many of them were believed to be lacking access to a stable housing situation.

Preston Christensen, 52, who was found near the South Platte River in December 1999, has been identified as just such a person, authorities said.

At the time, medical examiners speculated in their report that he was either Caucasian, Hispanic or Native American. They also thought him to be over 35 years old and weighing only 105 pounds.

The Denver Department of Public Health and Environment (DDPHE) announced a breakthrough in the case Wednesday after 23 years.

Initially, the Medical Examiner’s Office only had a clay model of the man’s face, but since then, investigators have been able to use DNA testing to identify him.

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“It took 23 years but our team at the Medical Examiner’s Office ID’d a man found dead in 1999. All they had was a clay representation of the man’s face. They used his DNA to ID a family member,” the DDPHE tweeted. “We hope the family of Preston Christensen, 52, from Minn., finally has some closure.”

Of the unidentified person cases the Medical Examiner’s Office has listed, three of 18 cases dating back to 1970 have been closed after identifications were made, with the other 15 still open.