The prisoner died Thursday at the Two Rivers Correctional Facility in Umatilla.

53-year-old Dean Wayne Guiley was found unresponsive in his unit around 7am Thursday. Efforts to revive him were unsuccessful and he was pronounced dead at 7:27 am.

Authorities continue to investigate, but did give any details about the circumstances surrounding his death.

Guiley was serving three kidnapping and one assault charge sentences, and had been in the facility since 2001.  His earliest date of release would have been  January 2043. He would be about 81 years of age at time of his release.

Two Rivers officials said more information will be released pending the investigation.