OKLAHOMA CITY (AP) — A 22-year-old man was found dead Wednesday inside his cell in the Oklahoma County Detention Center, the fourth inmate to die in the problem-plagued facility this year, authorities said.

Officials at the jail in Oklahoma City said in a press release that Parker Stephens was found unresponsive in his cell and was later pronounced dead at the scene. A spokesman for the facility, Mac Mullings, said Stephens did have a cell mate inside the cell when his body was found, but “at this point, there’s no reason to think the cell mate was involved.”

An internal investigation unit at the facility is looking into Stephens’ death, and the state medical examiner will determine the cause of death, Mullings said.

Stephens was being held on charges of assault and battery with a deadly weapon, manufacturing a controlled substance and possession of drugs within 1000 feet (304.80 meters) of a school, court records show.

Stephens is the fourth inmate to be found dead in the facility this year. Last month, a 40-year-old inmate was found beaten to death inside his cell. His cell mate has been charged with first-degree murder in that case. Foul play is not suspected in the deaths of two other men, ages 59 and 47, who died while in jail custody last month, Mullings said.

The jail has a long history of high staff turnover, overcrowding and escapes.

Last summer, two inmates, including a murder suspect, escaped by using sheets tied together to climb down the outside of the building from a 12th floor cell. And in October, two former Oklahoma jail employees and their supervisor were charged with misdemeanor cruelty counts after investigators found they forced inmates to stand handcuffed for hours and listen to the children’s song “Baby Shark” on repeat.

Oversight of the jail was transferred in 2019 from the Oklahoma County Sheriff’s Office to a nine-member jail trust.