AKRON, Ohio -- Investigators and the State Fire Marshal are still trying determine the cause of a fire that killed five children and their parents early Monday.

Fire department sources tell WKYC that hot charcoal from a Mother's Day barbecue may have been dumped into a trash receptacle and left near the front of the Fultz Street home.

The front of the house, built in 1925, sustained the heaviest damage.

Arson, however, has not been ruled out.

Channel 3 News has also learned that Patrick Boggs, the estranged husband of Angela Boggs, is now being held on a parole violation.

Angela died in the fire.

His Hazen Road apartment was searched by Akron police detectives late Monday night after he was taken into custody.

He was released in 2013 from prison and in 2001 had made threats to burn Angela.

He served 12 years for arson, aggravated arson, and domestic violence charges.

See photos from the scene: