One inmate died and seven others were hospitalized after suspected overdoses Saturday at Haynesville Correctional Center, a state prison in Richmond County, Va., authorities said Sunday.

Authorities discovered the suspected overdoses about 7:15 p.m., and one inmate was pronounced dead at 8:32 p.m., Lisa Kinney, a spokeswoman for the Virginia Department of Corrections, said in a news release. A medical examiner will ultimately determine his cause of death, she said.

The surviving inmates were sent to hospitals. All but one had been released by Sunday, Kinney said. Authorities do not know what caused the suspected overdoses, she said.

Visitation at the facility, in rural Richmond County, about an hour from the city of Richmond, was canceled Sunday.