BRISTOL, Conn. (WTNH) — Nicholas Brutcher had at least two interactions with Bristol police the night he opened fire, killing two officers, according to sources close to the ongoing investigation.

Those interactions will be key parts of the investigation into what happened that night.

A truck with Brutcher and his brother inside was pulled over and towed the night of the shooting, according to sources close to the investigation. They were picked up by their mother and brought home.

Later that night, police were called to the bar Bleacher for a dispute involving Brutcher.

He would go on to make a 911 call luring Lt. Dustin DeMonte, Sgt. Alex Hamzy, and Officer Alec Iurato to a home, where he would ambush them, firing more than 80 rounds, according to officials.

DeMonte and Hamzy were killed, and Iurato, who survived a gunshot wound to the leg, was able to fire the shot that killed Brutcher. Brutcher’s brother, who the three officers spoke to in the moments prior to the shooting, was also injured. It is not currently known what his involvement was.

“Police officers deal with people on a regular basis,” said Gary MacNamara, the retired police chief of the Fairfield Police Department. “Some people leave that interaction happy, and some people leave it angry. The people that leave it angry don’t necessarily jump towards violence at police officers. They’re going to want to find out the steps or the trigger that took it from being angry at police — towards violence at police.”

Bristol police ran a background check for News 8 on the brothers. Neither has a criminal record with the city.

Bristol has continued to heal since the Oct. 12 shooting and the officers’ funeral Friday. On Monday, officers boarded a bus to attend a New England Patriots game against the Chicago Bears, where they will be honored.

“They have been very generous to invite us up to the ballgame tonight, where we’ll be honoring our heroes,” Bristol Police Chief Brian Gould said. “We’re just very privileged to go up as a group. This is part of our bonding and healing process as we start to move forward, and we’re looking forward to the game tonight and tribute to our fallen and injured officers.”

The New York Yankees and the Miami Dolphins have paid tribute to DeMonte and Hamzy, as well.