Calvin Graham, a 56-year-old inmate being held in the Guilford County jail in downtown Greensboro, died in the county’s custody on Christmas Eve.

According to a statement from the Guilford County Sheriff’s Department, Graham was being treated by medical staff at the jail for “breathing issues” when he collapsed suddenly. The statement the Sheriff’s Department sent out Christmas afternoon reported that medical staff and detention officers in the jail “immediately began CPR and requested assistance from emergency medical personnel and first responders.”

According to Guilford County Sheriff Danny Rogers, who became the county’s new sheriff less than a month ago, the incident occurred around 4 p.m. on Monday, Dec. 24.

Both Guilford County Emergency Services and the Greensboro Fire Department responded when the call for help went out.  According to the statement from the Sheriff’s Department, the first responders got there “quickly” and they continued resuscitative efforts on Graham while he was being taken to Moses Cone Hospital.

Efforts to revive Graham were unsuccessful and he was pronounced dead at Cone Hospital at 4:56 p.m. – roughly one hour after the incident began.

At this time, the cause of death appears to be natural causes and there’s “no evidence of any foul play,” according to Sheriff’s Department officials.

The Sheriff’s Department states that it is following protocol and, as part of that protocol, the department immediately attempted to notify Graham’s next of kin. There’s no word whether that attempt was successful.

The department also stated that it will cooperate fully with the state medical examiner’s office to determine the exact cause of death.