BARNSTABLE, Mass. (WHDH/AP) — The trial of a man charged with killing a Massachusetts police officer in 2018 continued Friday with opening statements and initial testimony.

Thomas Latanowich, of Somerville, faces a first-degree murder charge in Barnstable Superior Court in the death of Yarmouth police Sgt. Sean Gannon.

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.

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

The defense lawyer said that Latanowich acted in self-defense and was afraid for his life because the officers were the aggressors. The lawyer added that his client never planned or expressed desire to harm Gannon.

Prosecutors stated that evidence presented during the trial will prove that Latanowich is guilty of premeditated murder.

Latanowich has been held without bail since he was arrested.

(Copyright (c) 2026 Sunbeam Television. The Associated Press contributed to this report. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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