TEGUCIGALPA, Honduras (AP) — Inmates from one of Honduras' powerful street gangs have killed six of their own inside a prison in northwest Honduras, authorities said Monday.

Prison guards found the bodies of six inmates from the Barrio 18 gang piled in a hallway during a routine inspection early Monday in the prison in Ilama.

“We have six people who have died in that penitentiary,” National Police Deputy Commissioner Marlon Lagos said to local media. “We are investigating and doing an inspection and also interviewing the coordinators of the different modules to determine the motive.”

Lagos said he did not know how the inmates were killed, but that forensic specialists were working the scene.

At least 90 members of the Barrio 18 gang are held inside the prison for a variety of crimes ranging from drug trafficking to extortion and murder.