Sweden is reeling days after the country’s deadliest mass shooting left at least 11 people dead, including the gunman, as investigators Thursday continued to look into the shooter's motive.

Witnesses who survived Sweden’s worst mass shooting have described horror and panic that gripped an adult education center west of Stockholm as the gunman killed at least 10 people.

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."