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."

The king and queen visited the scene of the tragic event that occurred on Tuesday and Swedish flags were flown at half-mast to honor the victims.

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.