Tehachapi State Prison is investigating after an inmate was assaulted and killed at the prison on Friday.

37-year-old Kevin Scott Mansfield of Tehachapi was assaulted just after 11 p.m. on February 16. Mansfield died just before midnight, according to the Kern County Sheriff's Office.

The incident is being called an in-custody death. A postmortem examination is scheduled to confirm the cause of death.