ARVADA, Colo. (CBS4) – A fire caused serious damage in Arvada on Sunday.

The flames burned two homes, two sheds, and a van on West 70th Drive. A neighbor saw the blaze and called 911.

(credit: Arvada Fire Department)

(credit: Arvada Fire Department)

Nobody was injured but fire crews say it’s a reminder to make sure smoke alarms are working.

(credit: CBS)

(credit: CBS)

“They weren’t home at the time, but had they been they would have been alerted because the smoke alarms were working and we just can’t emphasize enough how important that is,” Deanna Harrington with the Arvada Fire Department said.

Investigators are still trying to find out where and how the fire started.