Fire officials are trying to figure out what caused a fast-moving blaze in Massapequa Park.

A home on Balchen Street went up in flames Friday night at around 10. Fire officials told Newsday that they believe the fire started in the back of the home and was accelerated by a propane tank used for a grill on the deck.

They say the home is a complete loss now, leaving three residents homeless.

Three pets inside the home were killed by the fire.