A veteran detective and the murder suspect he was interviewing were killed Thursday, following an outburst of gunfire inside the Jackson, Mississippi, police headquarters.

The detective was talking with the suspect when an altercation broke out and shots were fired, Othor Cain, a spokesman for the Hinds County Sheriff's Department, told CNN.

Other law enforcement officers overheard the gunshots and rushed into the room, said a shaken Chris Mims, a spokesman for Mayor Harvey Johnson.

They found both people - the Jackson police detective and the suspect, neither of whom was immediately named - dead.

The incident occurred around 6 p.m. (7 p.m. ET). One hour later, the situation was contained, according to Cain.

The Mississippi Bureau of Investigation is leading the investigation to determine what happened, Mims said.

Jackson, a city of about 175,000 residents, is the capital of Mississippi.