SAN DIEGO — A 31-year-old inmate was found dead Thursday at San Diego Central Jail, authorities said.

Deputies walking by a holding cell on the second floor of the downtown building found the incarcerated man unresponsive, slumped over the partition wall next to a toilet, San Diego County Sheriff’s Lt. Chris Steffen said in a Friday news release. The man was alone when deputies found him.

Deputies and medical staff gave the man Naloxone — a medication used to reverse the effects of an opioid overdose — and performed CPR, but the man was pronounced dead at 6:28 p.m.

The Citizens Law Enforcement Review Board was notified of the death and responded to the jail.

Thursday’s marks the ninth in-custody death in the county so far this year. Last week, a 25-year-old inmate died after he was found unresponsive in his cell at Otay Mesa Detention Center.

Earlier this week, a motion was filed asking a federal court to address dangerous and deadly conditions at county jails. The complaint calls for the sheriff’s Department to do more in several areas, including preventing drug overdoses in jails, ensuring timely safety checks and more mental health follow-up for inmates.

In February, a blistering state audit revealed 185 inmates died in San Diego County jails between 2006 and 2020 — the most in the state. The report accused the sheriff’s department of failing to “adequately prevent and respond to” in-custody deaths.

FOX 5’s Jason Sloss contributed to this story.