The inmate who died at the North County Correctional Facility in Castaic Sunday “died a natural death,” according to homicide detectives.

The unidentified inmate had a seizure at approximately 7:05 a.m. Sunday at the correctional facility, located at 29340 The Old Road.

He became unresponsive and was pronounced dead while being transported to the facility’s infirmary.

“There’s nothing suspicious about (the death),” said Detective Philip Guzman with the Los Angeles County Sheriff’s Department Homicide Bureau. “It’s not going to be a criminal case.”

The Los Angeles County Coroner’s Office has not completed a medical exam as of Wednesday morning, however Guzman said “(the inmate) probably died of a heart attack, or some kind of natural cause.”

Homicide detectives investigate all inmate deaths “even if they’re not suspicious,” said Guzman.

The cause of death will be determined after an autopsy is completed, which will be conducted by personnel with the Los Angeles County Coroner’s Office.

The identity of the inmate is being withheld pending notification of next of kin.