Man accused of killing Yarmouth police sergeant pleads not guilty to slew of charges

BARNSTABLE, MASS. (WHDH) - The man accused of shooting and killing Yarmouth police Sgt. Sean Gannon pleaded not guilty to several charges in Barnstable Superior Court Friday and was denied bail.

A Barnstable County Grand Jury, which has been hearing evidence in the case of Gannon’s death since April 26, returned indictments last month formally charging Thomas Latanowich with murder, aggravated assault with a dangerous weapon, assault and battery with a dangerous weapon, use of a firearm in the commission of a felony, possession of a firearm without a license, carrying a loaded weapon without a license, possession of ammunition without an FID card, mistreating a police dog and being an armed career criminal.

Latanowich, 29, of Somerville, is accused of shooting Gannon in the head April 12 as he served a warrant at a home on Blueberry Lane in Barnstable.

Nero, Gannon’s K-9 partner, was also shot and wounded. The dog has since recovered.

Dozens of police officers lined the sidewalk outside of the courthouse as a shackled Latanowich was escorted back to prison. Yarmouth Police Chief Frank Frederickson said it was a way to show support for Gannon’s parents.

“We have a new normal,” he said. “This is the first time we feloniously lost an officer on Cape Cod.”

Since Gannon’s death, there have been six incidents in which police officers have been shot at in Massachusetts and Frederickson is hoping for change.

“The danger has increased dramatically,” he said. “In my 40-plus years of policing, it has never been like this in this area.”

Latanowich is being held without bail. He is due back in court in November.

(Copyright (c) 2026 Sunbeam Television. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)