US authorities have been quick to condemn the gun violence that's claimed eight lives at a Fedex parcel facility in Indianapolis

Several people were injured in the attack after the gunman opened fire in the late-night shooting, and then took his own life.

Investigators are still trying to determine a motive.

Mayor Joe Hogsett says they're all left with grief for those killed.

He says there's also grief for the Americans struggling to understand how tragedies like this occur again and again.