UPDATE: Prosecutor: Coffin involved only after Costello ‘brutally killed’

Gauvin Monaghan (left) and Maeson Coffin
Shawn McGrath
Staff Writer

Counts of murder and conspiracy to commit murder will be dismissed against the second man charged in connection with the beating death of a 78-year-old Plymouth man last year due to his lesser involvement in the alleged crime, according to Marshall County Prosecutor Nelson Chipman.
The prosecutor said Thursday 19-year-old Maeson Coffin, of Plymouth, is expected to plead guilty to charges of burglary, theft and auto theft.
If Marshall Superior Court I Judge Robert Bowen accepts the agreement, the murder and conspiracy to commit murder charges will be dismissed. The plea agreement was filed on Thursday.
Chipman said the plea agreement more accurately reflects Coffin’s involvement in Robert P. Costello’s murder in October 2016.
“The information we gathered, and after conferring with (Marshall County sheriff’s) Detectives Duane Culp and Jeff Snyder, convinced us that Mr. Coffin’s involvement with the crime began after Paul was brutally killed by (Gauvin) Monaghan,” Chipman said in an email. “We have insufficient evidence to prove beyond a reasonable doubt that Coffin knew Monaghan was going to kill Paul. That is not to say by a long shot that Coffin should not be held accountable for the acts he did commit and for which can be proven beyond a reasonable doubt.”
Bowen sentenced Coffin’s co-defendant, 19-year-old Gauvin Monaghan, to 65 years in prison earlier this month for beating to death Costello in October 2016.
“Gauvin Monaghan was a serial killer who fortunately got caught after his first murder,” Chipman said following Monaghan’s sentencing hearing.
Monaghan, who is from Watertown, N.Y., but had been living in Plymouth, pleaded guilty to murder in November in a deal with prosecutors. Charges of conspiracy to commit murder, burglary, auto theft and theft were dismissed as part of the plea agreement.
According to court documents:
Sheriff’s deputies were called to Costello’s home in the 15000 block of Lincoln Highway after Costello’s friends said they hadn’t seen him for a couple of weeks. Officers discovered Costello’s body near an out building when they searched the property.
Costello’s 2007 Buick LaCrosse and cell phone were missing. Investigators contacted the cell phone service provider and determined it was in New York State.
A day after Costello’s body was discovered, Monaghan’s girlfriend told investigators that Monaghan and Coffin had been living on Costello’s property. She said Costello went to Monaghan and Coffin in late October to collect rent and an argument ensued. Monaghan’s girlfriend said Monaghan was irate and said “he should just kill Paul Costello and steal his car,” according to court records.
Monaghan was arrested in Watertown, N.Y., driving Costello’s Buick.
Coffin had been scheduled to stand trial in January.
Read more about this in Friday’s edition of the Pilot News.