Brian Leonard Gittings, 44, of Santa Rosa, told a correctional deputy at 4:20 a.m. that he was struggling to breathe, Lt. Steve Brown said.
The deputy called for medical assistance but Gittings' condition worsened and he was given CPR, Brown said.
Paramedics arrived and continued CPR, and Gittings was taken to Kaiser Permanente Medical Center in Santa Rosa where he was pronounced dead at 5:19 a.m. Sunday.
On Nov. 25, Gittings had been taken to Sutter Medical Center in Santa Rosa after complaining of abdominal pain, Brown said. He was evaluated at the hospital and then returned to the jail, Brown said.
Gittings was in custody on charges of assault with a deadly weapon and violation of probation.
An autopsy is scheduled for this morning.