Last night's had burned through much of the house before engines could get to the scene, destroying any evidence of that would indicate how the blaze began.
Wellesley’s Deputy Chief Jeffrey Peterson said the homeowners left the house last night around 8 p.m. and returned about two to two-and-a-half hours later when they found the first floor on fire.
“That fire got a good head start,” Peterson said. “When we arrived on the scene the fire was starting to push out the doors and the windows.”
Peterson said smoke, heat or flames damaged all of the interior. The fire had burned a hole in the floor of the room of origin.
Officials stayed on scene through the night to monitor a few of the “hot spots” that remained. The state fire marshal said the cause was undetermined and not suspicious, according to Peterson.