The Belfast man accused of fatally shooting a mother and injuring her son in August pleaded not guilty by reason of insanity to the charges Wednesday, Oct. 30.

Gilday, 44, shackled at the hands and feet, was brought into the courtroom at about 8:30 a.m. where he entered his pleas before Justice Robert Murray with his attorney, Philip Cohen of Waldoboro, at his side. Gilday is charged with intentional or knowing murder, attempted murder with a firearm and elevated aggravated assault with a firearm.

Cohen added that Gilday was pleading not guilty by reason of insanity after Justice Murray read each charge.

A Knox County Grand Jury indicted Gilday on the charges in October.

Gilday faces a possible life-in-prison sentence on the murder charge and a mandatory minimum 25-year sentence. He could be sentenced to up to 30 years on the elevated aggravated assault charge, according to previously published reports.

A Harnish hearing was scheduled to take place during the court appearance, but Cohen asked that the hearing be continued day-to-day, which was granted. Justice Murray also ordered Gilday to continue to be held without bail at Two Bridges Regional Jail in Wiscasset.

Harnish hearings are used for cases such as this one to to determine if bail will be set and if it is, what conditions will be in place while the defendant is free on bail.

Justice Murray also ordered Gilday to undergo a medical evaluation as requested by Assistant Attorney General Leane Zainea who is prosecuting the case. Cohen had objected to the evaluation previously, but withdrew the objection during Wednesday's court appearance.

The charges stem from an Aug. 28 incident in which Gilday forced his way into the 162 Waldo Ave. home of Mathew Day, 22, of Belfast. Gilday shot and killed Day's mother, 55-year-old Lynn Arsenault, before shooting and wounding Day.

According to an affidavit from Maine State Police Detective Ryan Brockway, who learned of the shooting at 5:30 a.m. Thursday, Aug. 29, he went to the Belfast Police Department to meet with Maine State Police Detective Darryl Peary, who told Brockway Day was taken to Eastern Maine Medical Center by helicopter to be treated for a gunshot wound.

Peary also told Brockway that Day identified Gilday as the shooter.

The affidavit indicated Arsenault stayed with Day at the Waldo Avenue home on days when she worked at Bank of America. Arsenault also had a registered address in Garland.

Brockway stated in his affidavit that Peary spoke with a registered nurse who said Day had been shot in the arm and stomach area with bird shot.

Belfast police learned of the shooting after receiving a report of gun shots and screaming in the vicinity of 162 Waldo Ave. at 10:56 p.m. on Aug. 28. When officers arrived, they found a male subject, later identified as John Riley, who told officers to hurry.

Riley told police he did not have a gun and the shooter had left the home, the affidavit stated.

When officers entered the home through a back door, Brockway said in his affidavit police could see a broken window with a fist-sized hole in the glass. Officers also observed a male subject lying across a female subject on the floor of the kitchen area.

The male subject, later identified as Day, was able to talk to police and identify Gilday by name as the shooter. While talking to Day, Belfast Police Sgt. Brian Lunt discovered several unfired shotgun shells and bird shot on the kitchen floor, according to the affidavit.

Riley told police Gilday came to the door of the home and was met by Day. "The door opened partially before Day attempted to close it, at which point the glass was blown out of the door and the door was kicked in,” Riley told police, according to the affidavit.

Gilday then shot Arsenault, threatened to kill everyone in the home, and then shot Day, the affidavit said.

Brockway's affidavit indicated Riley also identified Gilday as the shooter.

Police eventually located and arrested Gilday at Pen Bay Medical Center the morning of Aug. 29.

Gilday's professional profile posted on, indicated he was employed as a tax examiner with the Maine Revenue Service, and also as the the owner of Spinnaker Financial LLC in Belfast. An internet search does not find a website or other information confirming the existence of the business.

Tanya Mitchell contributed reporting to this story.

Republican Journal reporter Ben Holbrook can be reached at 338-3333 or at