Remains recovered from Columbia River may belong to Prosser man reported missing 26 years ago

The Umatilla County Sheriff's Office is working to confirm that remains found in a submerged vehicle in the Columbia River over the weekend are those of a Prosser man who went missing 26 years ago.

According to the Sheriff's Office, a couple was scuba diving in the Columbia River at the Hat Rock State Park boat launch in Umatilla County on October 17th. The couple reported that they had found a submerged Ford Ranger pickup with Washington license plates in about 20 feet of water just past the end of the docks.

Dispatch checked the license plate and realized that the vehicle was connected with a missing person case from the Prosser dating back to 1993.

Mr. Maynard Koen, who was born in 1911, was reported as a missing person to Prosser Police in August of 1993. 

The Sheriff's Office coordinated with Columbia Basin Dive & Rescue and D&R Towing from Hermiston to help in recovering the vehicle from the river.

After approximately 2 hours, the vehicle was removed from the water and transported to the Umatilla County Sheriff’s Office for further investigation.

Human skeletal remains and a driver's license issued to Koen were located inside the vehicle, which investigators say appears to have been submerged since about the time Koen was reported missing.

The Oregon State Medical Examiner’s Office will work to positively identify the remains.