A former deputy chief of the Stoughton Police Department has been decertified as a cop due in large part to his alleged relationship with Sandra Birchmore before her death.

The Massachusetts Peace Officer Standards and Training (POST) Commission wrote that Robert Devine “has a pattern of unprofessional police conduct” in its final decision letter revoking his law enforcement certification.

The 30-page “initial decision” document attached to the final decision details that alleged misconduct and groups it into two umbrella categories.

The first category is alleged misconduct in late 2014 involving Devine — then the deputy chief of police for SPD — improperly directing investigations into a woman he was having an extra-marital affair with.

While the allegations are heavily redacted in the document, he apparently told the Massachusetts State Police the woman was harassing his family. The MSP launched an investigation, all the while Devine allegedly maintained a romantic and sexual relationship with the woman.

The allegations were sustained in an internal review and Devine was suspended for sixty days and then demoted from deputy chief to patrol officer, a rank he maintained until his retirement while under investigation yet again in 2021.

The second category is the one involving Sandra Birchmore, who was found dead in her Canton apartment on Feb. 4, 2021. While her death was first determined to be suicide, federal investigators later charged another Stoughton cop named Matthew Farwell with murdering her, a case that continues in the federal court in Boston.

Both Farwell and Devine worked in the SPD Explorers Program, which Birchmore joined in 2010 as a 13-year-old girl and then left in 2016 when she graduated from high school.

The POST Commission says that Devine maintained inappropriate contact with Birchmore on Facebook under the alias “Marty Riggs,” including communicating with her on Feb. 1, 2021, when she is believed to have been killed.

“The Division maintains that Devine met with S.B. for a sexual encounter while he was on-duty as a law enforcement officer, that he had inappropriate communications with S.B. through Facebook Messenger while on duty, and that he was untruthful about his misconduct during the related internal affairs investigation,” the decision states.

The hearing to review Devine’s certification featured testimony from current Stoughton Police Chief Donna McNamara, Kingston Police Chief Brian Holmes, former Explorers Program participant Hailey Hogan, and Devine himself.

Devine testified that his social media accounts were broken into and messages sent that he never sent. He said he complained to the social media companies but the problem was never fixed. This went on from 2015 to 2020 so the hearing officer “deems that this testimony in the context of this matter is curiously convenient for his defense of the allegations of his conduct involving S.B. discussed below, and inherently incredible.

Devine joined SPD in 1999 after a career in the Coast Guard and in the City of Boston’s Marine Environmental Response Unit. He was promoted to sergeant in 2004, lieutenant in 2006, and deputy chief in 2008. The Respondent was admitted to the Massachusetts Bar on January 11, 2021.

The POST Commission says it linked the “Marty Riggs” account to Devine due to circumstantial evidence: “the author of the text messages became a lawyer on the same date that the Respondent was admitted to the bar, and that the author had the same work schedule as Devine.”

Incident Summary

BPD responded to 140 incidents in the 24-hour period ending at 10 a.m. Saturday, according to the department’s incident log. Those included seven aggravated assaults, one commercial burglary, two residential burglaries, two thefts from a vehicle, two auto thefts, and 12 instances of miscellaneous larceny.

Arrests

All of the below-named defendants are presumed innocent until proven guilty.

— Tonnisha Thomason, 364 Geneva Ave., Boston. Larceny less than $250.

— Frank Brown, no address listed. Larceny less than $1,200.

— Jerald Swankowski, Roxbury. External warrant arrest.

— John Moran, 42 Sheridan Ave., West Springfield. Disorderly conduct.