Unalaska, AK – On Friday the Coast Guard will begin its formal inquiry into what caused a fishing boat to sink in the Bering Sea on Sunday morning. Five men were killed when the Alaska Ranger sank in the early hours of Easter Day, but why the boat went down is still unclear.

Although they haven't provided details yet, investigators will almost certainly be looking at how closely safety regulations were followed on the ship. KIAL's Charles Homans reports.