Officials in Sweden have vowed to determine why a man killed 10 people, and apparently himself, in an unprecedented attack that's shaken their "society to its core."

Police said at least 10 people were killed at a school on Tuesday, in what has been described as the worst mass shooting in Sweden’s history. The suspected perpetrator also died. The Robertson County Sheriff’s Office is searching for a suspect after police found a body while responding to a welfare check in Greenbrier Tuesday.