BARNSTABLE, MASS. (WHDH) - The murder trial for a man accused of killing Yarmouth Police Sgt. Sean Gannon in 2018 continued Monday with testimony from Thomas Latanowich, who took the stand and told the court that he opened fire on the officer in an act of self-defense.

Latanowich, 33, of Somerville, faces a first-degree murder charge in Barnstable Superior Court in connection with Gannon’s death.

Gannon, 32, the department’s K-9 officer, was killed in April 2018 while he and other officers were serving an arrest warrant for a possible probation violation at a Barnstable home. Gannon’s dog, Nero, was also shot but survived.

Latanowich, described by prosecutors as a career criminal with a lengthy record, is also facing other charges, including assault and battery with a dangerous weapon, firearm possession without a license, and mistreating/interfering with a police dog.

Latanowich testified about work that was being done on a nearby home and the sound of nail guns that could be heard when officers entered the home to find me, telling the jury that he was confused and unable to hear the officers who were calling out to him.

“Only thing I heard was those pops,” Latanowich said when asked if he could hear anything from inside the house. When asked whether or not he thought police officers had entered the home, he answered, “Absolutely not.” He added that he no intention of killing Gannon.

Latanowich also told the court he had been dealing cocaine and that he survived a drive-by shooting, claiming he hid in the attic of his friend’s home because the people who wanted him dead were coming after him.

“I was scared, I was nauseous, I was having difficulty breathing,” Latanowich said. “When I was underneath the insulation, I was fighting to stay awake.”

Latanowich later said that he tried to save Nero after his gun accidentally went off.

“I tried putting compression on where I thought the blood was coming from…He was just nipping my hand.”

Richard Cazeault told the court last week that he was packing up his equipment at a nearby construction site when Gannon was shot.

“I was going back and forth to my truck for about 20 minutes or so and there was nothing,” Cazeault recalled. “Then as I was walking towards my truck I heard a pop.”

A forensic scientist testified that she found bloodstains on a stack of money at the scene of the murder, as well as gunshot residue on the hands of Latanowich.

Prosecutors say Latanowich was hiding in the attic and that officers warned him that they were coming in, making multiple announcements.

“I saw Officer Gannon begin to take the insulation down. As soon as he started to pull the insulation back, the sound of a muffled bang was heard…A gunshot,” Officer Sean Geary testified earlier in the trial. “As soon as that gunshot was heard, Officer Gannon, who was on his knees at the time, fell straight forward.”

Crystal Bearse, the mother of Latanowich ‘s daughter took the stand earlier in the trial, telling the court that her former partner sent her many incriminating texts after Gannon was fatally shot.

“They got me surrounded,” I’m shooting it out,” and “It’s too late” were some of the texts that Bearse read aloud.

Defense attorney Joseph Krowski argued that the officers didn’t handle the search for his client properly.

Krowski previously told the court that his client acted in self-defense and was afraid for his life because the officers were the aggressors. 

Prosecutors have stated that evidence presented during the trial will prove that Latanowich is guilty of committing the murder with deliberate premeditation.

Latanowich has pleaded not guilty and has been held without bail since his arrest.

Closing arguments are expected to be delivered on Tuesday.

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