PLEASANT POINT, Maine — A second fire of unknown origin in a week at the same house on the Passamaquoddy reservation at Pleasant Point finished it off over the weekend, burning what was left to the ground, fire officials reported Monday.

“It was pretty much destroyed by the last fire,” said Pleasant Point Fire Chief Alan Sprague, who said the house was vacant. “There wasn’t much left to it.”

A representative of the state fire marshal’s office was on the scene investigating Sunday, according to Sprague.

Both fires were of undetermined origin, Sgt. Timothy York, an investigator for the fire marshal’s office, said Monday. He declined to discuss the probe into the fires.

The latest fire was reported to Washington County Regional Communication Center at about 2:30 a.m. Sunday. Pleasant Point firefighters responded along with others from Perry and Eastport.

What was left of the house — it was considered a total loss after a fire on Oct. 20 — already was fully involved in flames when firefighters arrived, according to Sprague, who was not on the scene but was briefed later by other fire officials. Firefighters devoted their efforts to protecting neighboring properties, he said.

“It’s totally flat now,” Sprague said.

Like the earlier fire at the split-level home on Warrior Road, the blaze was of undetermined origin, Sprague said. Electricity had been turned off at the property following the first fire.

No one was home when the fires were reported and no firefighters were injured.

The first blaze was reported about 11:30 p.m. the previous Sunday.

Someone was in the process of moving out of the house and new occupants were in the midst of moving in about the time of the first fire, Sprague reported earlier.

The first fire caused heavy damage to the basement and first floor and destroyed half the roof.