AUSTIN (KXAN) — A 23-year-old man died Tuesday morning after he was found unresponsive in his cell at the Travis County Jail.

The sheriff’s office says Naquan Jamar Carter was found at 9:56 a.m. and officers and medical staff immediately began CPR.

He was pronounced dead at 10:39 a.m. The Internal Affairs Unit, the Texas Rangers and the Medical Examiner’s Office are investigating, as is standard for a death in custody.

The sheriff’s office says evidence indicates Carter likely died of natural causes.

A final autopsy report is pending toxicology results. A sheriff’s office spokesperson says Carter was in custody on a charge of assault of a public servant. 

Earlier this month, a 55-year-old man found lying on the floor of his cell later died at the hospital

In April, two inmates were found dead in their cells on the same day. Deputies said the deaths were unrelated. 

The Travis County Sheriff’s Office announced last year it had received a passing grade with no deficiencies found or corrective measures required for the past 10 years.