The investigation into a fire that claimed the lives of three Front Royal residents back in April is closed.

Front Royal police say arson has been ruled out and the cause of the fire is officially undetermined.

There are a few possible theories of what started the fire. Investigators say it could have been started by cigarettes. They also say landscaping mulch may have built up heat and burst into flames.

"We located two witnesses that indicated that during the night before the fire, hours before the fire, they did smell smoke in the area," says Chief Ron Williamson, Front Royal Police Department. "When they went and checked, they did not see any flames. We think that was when the fire was starting, and it went from there."

Stephen Cook, 32, along with his two daughters Madison, 8, and Stevie, 4, died in the fire.

In the weeks after the fire, the Front Royal and Warren County communities made donations to the Cook family.