BANGOR, Maine — Brian Pelletier’s fingerprints on a burned mailbox, located on Parker Street in Brewer and found at the same time law enforcement were investigating an arson just down the street, is evidence that links Pelletier to a September 2007 house fire.

That is what Michael Roberts, deputy district attorney for Penobscot County, said Monday in his opening statements in the arson trial of Pelletier, 25, in Penobscot County Superior Court.

A witness who identified Pelletier as the man she saw acting strangely moments before the fire at 121 Parker St. was noticed and is another key piece in the case against Pelletier, he said.

Defense attorney Thomas Matzilevich says another man who threatened to set the house on fire in the days leading up to it catching fire committed the crime.

“That threat did not come from Brian Pelletier,” he said. “Brian Pelletier had no reason … to burn them out of house and home.”

A barking dog alerted residents in the multifamily apartment building on Parker Street that there was an emergency on Sept. 22, 2007. The fire destroyed the entire back side of the dwelling, displaced two families and a group of friends living there and killed three pets — two cats and a dog.

Pelletier was drinking alcohol at a party in the top-floor apartment, rented by his brother Shawn Pelletier, hours before the blaze broke out, both attorneys said.

“He was drunk and angry,” Roberts said.

Pelletier “had so much to drink that … he made a fool of himself,” Matzilevich said, adding that the others in the apartment with him locked him out.

Pelletier then walked to his home in Bangor, his attorney said.

Roberts has a different take on the situation. He said his witness will testify that she saw Pelletier smoking a cigarette near the burned mailbox around 5:30 a.m. on the day of the fire, then minutes later pacing back and forth in front of his brother’s apartment building.

The man the witness says is Pelletier then started a small fire at the front of the building and put it out before he walked behind the building, according to Roberts. At 6 a.m. she was calling 911 to report the fire, he said.

The witness was presented with a photo lineup by Stu Jacobs, Fire Marshal’s Office investigator, and “the person she points at is the defendant, Brian Pelletier,” Roberts said.

Matzilevich argued that the female witness also gave a description of the clothing the suspect was wearing and it did not match the clothing Brian Pelletier had on that day.

“There are going to be holes in the state’s case,” he said.

Monday’s testimony started with a man who lived on the first floor of the apartment building with his adult son. During a short break, Roberts said the state also would be calling other apartment residents, neighbors, and a woman, who was seven months pregnant at the time of the fire, who was visiting a friend at the top-floor apartment rented by Pelletier’s brother. Shawn Pelletier was not at home the night of the fire.

Brewer police, investigator Jacobs, and a Maine State Police evidence collector also are scheduled to take the stand. Whether Pelletier will take the stand in his defense is not known. Superior Court Justice Michaela Murphy sequestered the five male and nine female jurors, saying they could not discuss the case, even among themselves.

The trial is expected to run until Tuesday afternoon or Wednesday.