CENTENNIAL — Investigators say a fire that injured eight people, one critically, in a suburban Denver apartment complex was arson.

The Arapahoe County Sheriff's Office said Tuesday it was still investigating the fire at the Copper Terrace Apartments in Centennial. Investigators want witnesses with photos or video to come forward.

Eight people were initially hospitalized after the fire early Monday, but some have been released. At least some of them were injured while trying to escape the burning three-story building. Some neighbors threw a rope made out of sheets up to one family and held on as members slid down onto a mattress in the back of a pickup truck.