Ryan Ernest Roy was acting "paranoid" in the days leading up to when he killed his mother in her home near Hartland on March 2, 2015, a court heard on Wednesday.

A sentencing hearing is taking place in the Court of Queen's Bench following Roy's guilty plea in November to charges of second-degree murder and arson.

In a statement of facts read by Crown prosecutor Chris Levine and agreed to by Roy, Roy's girlfriend told police after the killing that Roy was being paranoid and left their home in Saint John.

Roy's sentencing hearing for second-degree murder heard Wednesday the 25-year-old thought his girlfriend was planning to kill him and he always carried a knife.

Roy and his girlfriend stayed with her parents on Feb. 28 and March 1, during which time she said Roy acted paranoid and called police to report break-ins to their vehicle, but nobody was found to have broken into the vehicle.

Phyllis Roy

The body of Phyllis Roy, 52, was found in her Peel home, following a fire on March 3, 2015. (RCMP)

When he was taken to the hospital in Waterville, Roy was found to have opiates, methamphetamines and oxycodone in his system. Roy declined mental health treatment and was given Ativan to calm him down.

Roy's girlfriend dropped him off at his mother's home on March 1 at 7:14 a.m. He slept most of the day and his father found a pill bottle.

At 11:30 p.m. that day, Roy woke his parents and asked to be taken back to the hospital. His father went to stay at their daughter's house.

At 4:30 a.m. the following morning, a fire was reported at the Roy home.

Fire crews arrived to find the residence fully engulfed in flames. The victim's husband, Joseph Roy, found out about the fire at 8 a.m. when his phone re-charged.

Phyllis Roy's body was later found inside with multiple stab wounds. The gas jets from the garage had been opened to start the fire. Ryan Roy had taken his mothers car and went off the road.

Joseph Roy and daughter Sara Roy read victim impact statements to the court Wednesday.

Roy's father told him: "You took the life of the one person who was trying to save yours."

Sara Roy told the court she felt her heart was ripped out of her by the death of her mother.

But after months of anger, she said to her brother in court: "With all the strength that's in me, I forgive you Ryan."

Ryan Roy paid attention to Wednesday's proceedings, but displayed no emotion for the most part.

However, when the Crown prosecutor said Roy wrote "F--k my mom" and similar statements on his room walls, Roy objected in court, saying "F--k you!"

Justice Tracey DeWare threatened to have Roy removed from the court and said he appears to have a mental disorder.

A psychiatric assessment found Roy did not have a mental disorder, said Levine, but the court should be concerned about his aggressiveness.

DeWare said Roy's behaviour before and after the incident is not 'normal' behaviour.

The Crown prosecutor said the murder presents a threat to the public, shows no remorse, and argued that because it was a case of a son killing his mother, the crime is more heinous.

Levine recommended a sentence of eight years in prison for arson and and life in prison with no parole eligibility for 19 years on the murder charge.

Defence lawyer Ed Derrah said Roy had a history of abuse, anger and multiple diagnoses of underlying medical health issues that were not treated properly, which he self-medicated with drugs.

Derrah recommended Roy serve 15 years in prison before becoming eligible for parole.

Given the chance to address the court, Roy stood and said: "I got nothing to say."

DeWare is to impose her sentence at 11 a.m. Friday.