BISHOPVILLE, S.C. (AP) -- A coroner says the seven inmates killed during a South Carolina prison riot earlier this month all bled to death from stab wounds.

Lee County Coroner Larry Logan said Tuesday all the inmates had several stab or cutting wounds inflicted inside Lee Correctional Institution on April 15 and 16.

Authorities say inmates in three wings of the maximum-security prison fought uninterrupted for several hours in a battle over territory and contraband. Inmates reported seeing fellow prisoners slowly die as prison officials tried to gather enough people to restore order.

At least 20 inmates have been killed by other inmates in South Carolina prisons in the past 16 months.

The State Law Enforcement Division continues to investigate the riot. No charges have been filed.

Twenty-two inmates were hurt.