MORRISTOWN, N.J. - Morris County authorities believe a fire that forced about 20 people to flee a multifamily home and injured a firefighter was purposely set.

Morristown firefighters and police went to the residence around 4:30 a.m. Sunday after several neighbors called 911, county Prosecutor Robert Bianchi said.

As residents were safely evacuated from the home's upper floors, firefighters battled flames and heavy smoke. But a portion of the house soon collapsed, and firefighter Dominick Prizzi was hurt when debris knocked off his helmet and face mask.

Prizzi was taken to Morristown Memorial Hospital, where he was treated for smoke inhalation and other injuries. He was released a short time later, Bianchi said.

Bianchi said the fire was being investigated as an arson, but details on how it started were not disclosed.

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