Officer slaying suspect had violent criminal history; wanted for violating probation on gun charge

Heavily armed Barnstable Sheriff officers escorted Thomas Latanowich from the Barnstable County Courthouse after his arraignment for the killing of Yarmouth k-9 officer Sean Gannon.
John Tlumacki/Globe Staff
Heavily armed Barnstable Sheriff officers escorted Thomas Latanowich from the Barnstable County Courthouse after his arraignment for the killing of Yarmouth k-9 officer Sean Gannon.

BARNSTABLE — The man suspected of murdering Yarmouth Police Officer Sean M. Gannon inside a Marstons Mills house was wanted for violating probation — and faced a maximum of just 210 days behind bars if a judge eventually ruled he needed to return to prison.

Now, Thomas M. Latanowich faces decades in prison for allegedly shooting the 32-year-old Gannon and for wounding Gannon’s police dog, Nero, during a confrontation at 109 Blueberry Lane as Gannon and other officers tried to capture Latanowich for probation violations, officials said.

According to the Massachusetts Probation Service, Latanowich was not at home April 4 when a probation officer visited and failed to show up one day later to take a drug tests he is required to take since pleading guilty in Barnstable Superior Court to gun and drug charges, records show.


The probation service obtained a warrant for his arrest last Friday, according to Coria Holland, spokeswoman for the state probation service.

Yarmouth police officer fatally shot in Barnstable while serving warrant

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The 29-year-old Latanowich pleaded not guilty to a charge of murder in Barnstable District Court, according to Cape and Islands District Attorney Michael O’Keefe.

Latanowich, according to officials and news reports, has an extensive adult criminal history that generated 28 cases against him in Barnstable District Court alone. His record also includes a four-year state prison term, and he has more than 110 entries on his criminal history.

Many of the district court cases, which date back to 2005, were dismissed. Sometimes the cases were dismissed when the victim refused to go forward, and in at least two cases he was found not guilty by a judge, a Globe review of the Barnstable District Court records indicates.

Officials said Latanowich had ties to Somerville, but a neighbor said Latanowich has a relative who lives in Somerville but has no other connection. According to the Cape Cod Times, Latanowich was arrested by Yarmouth police when he was 18 years old.


In October 2016, Latanowich was arrested and charged with allegedly strangling a pregnant woman and vandalizing her vehicle, court records reviewed by the Globe show. The case was dismissed, however, when the woman asserted her Fifth Amendment privilege against self-incrimination, records show.

In December of that year, Latanowich was arrested again after he allegedly stabbed a man on Route 28 in West Yarmouth. The victim’s girlfriend told police that she was driving with her boyfriend and stopped at a traffic light in West Yarmouth when Latanowich walked up to their car, opened the passenger side door, and attacked him, according to the Yarmouth police.

The victim, who’d just been released from prison, suffered a severe stab wound to his right wrist. Latanowich, who was out on probation, was arrested a few hours later — but that charge was also dismissed, records show.

At the time of that arrest, Yarmouth police described Latanowich as “a violent career criminal” with 111 prior criminal charges in Massachusetts.

But the case that led Gannon to Blueberry Lane dates back to 2009, when Latanowich was arrested by two Cape Cod police departments, leading to illegal gun possession and drug charges. The two incidents were combined into one when he pleaded guilty in Barnstable Superior Court in 2010 and was given a five-year sentence — with credit for 203 days jailed awaiting trial.


He was sent to state prison, where he was paroled once — and sent back for violating parole — before completing his sentence on June 24, 2014, when he was released. However, he was still on probation until Nov. 1, 2018, records show.

The drug charges were dismissed by order of the Supreme Judicial Court in 2017 because they were related to disgraced state chemist Annie Dookhan, records show. The dismissal of the drug charges, however, did not end his probation, and as of last week, he was supposed to be at home if a probation officer showed up and supposed to submit to random drug tests, record show.

Travis Andersen can be reached at Follow him on Twitter @TAGlobe. Emily Sweeney can be reached at Follow her on Twitter @emilysweeney. John R. Ellement can be reached at Follow him on Twitter @JREbosglobe.