SHERMAN, Texas (KTEN) — An investigation is underway into the death of Haywood Riggins of Denison, who was being held at the Grayson County Jail.

The Grayson County Sheriff's Office said the 65-year-old was found unresponsive in his cell early Monday  morning. He died after jail staff and Sherman Fire Rescue responders initiated medical assistance.

Riggins had been jailed since June 2 after being charged with driving while intoxicated.

An investigation by the Texas Rangers is standard procedure when someone dies in custody.