Authorities are investigating the death of an inmate at the Clatsop County Jail.

Jay Christopher Jamieson, 38, died Friday at about 2:10 p.m. at Columbia Memorial Hospital in Astoria. An autopsy conducted by the state medical examiner on Saturday found Jamieson died of natural causes.

Jamieson was booked at the jail on Thursday night on charges of unlawful delivery of heroin, unlawful delivery of a controlled substance to a minor, child neglect in the first degree and endangering the welfare of a minor after a search warrant was served on his residence in Warrenton.

The death is being investigated by the Clatsop County Major Crime Team.