Thomas Latanowich is charged with killing Yarmouth Police Sgt. Sean Gannon in 2018. Gannon was shot and killed while he and other officers were serving an arrest warrant at a home in Marstons Mills on April 12, 2018. Gannon’s K-9 partner Nero was also shot, but survived. Latanowich was wanted for violating his probation and was holed up in the attic of the house when investigators say he shot Gannon and Nero. 'Officer Gannon reached up to pull that piece of insulation down and as soon as that insulation was pulled down they heard a pop and observed Officer Gannon fall face-first onto the insulation in the attic. At that point, you will hear that they realize that Officer Gannon had been shot,' prosecutor Michael Trudeau said. Gannon was just 32 years old.