LILLINGTON – Authorities said eight inmates have been hospitalized after overdosing on illegal drugs.

A spokesperson of the Harnett Correctional Institute said the inmates got sick after using synthetic marijuana Saturday.

Four inmates were admitted to the hospital. Three remain in the emergency room being observed as of Sunday. One was sent back to prison.

Lillington Police say they are investigating the incident and the prison officials.

The prion is medium security and can hold about 850 inmates.