The death of an Oklahoma County jail inmate is under investigation.

About 1:40 p.m. Sunday, officers discovered Jeremy Birchfield, 45, unresponsive in his assigned cell, jail officials said in a news release.

Officers called for medical staff and started performing CPR.

EMSA and the Oklahoma City Fire Department personnel arrived and continued life-saving measures. Birchfield was transferred to the hospital but did not survive.

Birchfield was the fourth Oklahoma County inmate to die this year.

His family has been notified.

Birchfield was booked into the jail on Friday by the Warr Acres Police Department. He was being held on a $265,000 bond, but had not yet been officially charged.

This article originally appeared on Oklahoman: Inmate found unresponsive in Oklahoma County jail cell later dies, authorities say