An RCMP officer testifying at the inquest into the deaths of Patricia Hennessey and her four-year-old son Nash Campbell Monday afternoon, said police were involved in dozens of incidents between Hennessey and Nash's father Marc Campbell.

The bodies of Hennessey and her son were found in a burned-out Jeep on June 21, 2013 in St. Felix, just outside Tignish, P.E.I. A police investigation ruled the deaths a murder-suicide and showed both had prescription drugs in their systems when they died of smoke inhalation.

Of the nearly 40 reported incidents between Nash's parents, 10 fell under the category of domestic violence, RCMP Const. Cheryl Duffy told the inquest, which is being held this week in a Summerside courtroom.

Sources told CBC News that Hennessey had lost custody of her son the day before the murder-suicide and was supposed to turn Nash over to his father that morning.

Duffy said on one occasion, in March 2011, Hennessey was arrested for impaired driving and damaging Marc Campbell's vehicle.

Nash Campbell

Sources told CBC News that Patricia Hennessey had lost custody of her son Nash Campbell the night before the murder-suicide. (Facebook)

As police took her to jail she told them she would take her own life and her son's, because of what police had done to her that night.

Police found Nash alone at home on that occasion, the front door was unlocked.

Hennessey pleaded guilty to impaired driving and was sentenced to three days in jail, a two-year driving probation and 15 days of jail for causing damage to Campbell's vehicle.

On another occasion, Marc Campbell told police Hennessey had threatened to "make him pay."

Duffy said the RCMP felt the complaints were escalating because both parents were trying to make the other look bad due to a family court dispute. However, she said police thought the agencies involved with the families may not have been aware of complaints to police.

'Hands are tied,' say RCMP

Duffy also brought forward a police report of Hennessey attempting suicide in May 2011. Hennessey left a note, saying the attempt was due to a custody battle over Nash.

Police said, the note read, "I can't take it anymore. Tell Nash I love him."

With the exception of Hennessey's impaired driving and mischief charges, all charges against Campbell and Hennessey were withdrawn or stayed.

Duffy said she undertook a file review of all the police interactions with Nash's parents.

She said in the future it would help to have a committee of all the agencies involved to help families in crisis.

When a juror asked why police can't get involved to settle disputes such as these, Duffy said "their hands are tied" and that "it's frustrating" for police. They can't take a child from their parents if the child is not at immediate risk.

Duffy said there were attempts to get all the parties involved together for a meeting to resolve the dispute. But when a date was set, the child and family worker wasn't available, although all agencies involved did continue to work separately to try to resolve the issue.

The family was in crisis when the family court dispute was determined to be going ahead, said Duffy. At that point, complaints to the RCMP from Hennessey and Campbell rose 200 per cent.

Monday was the first day of the inquest, which is presided over by Prince County coroner Dr. Roy Montgomery and heard by a panel of six jurors.

Badly burned

In the morning, the inquest heard from several witnesses who saw Hennessey's Jeep on fire, including firefighters, RCMP officers and members of the public.

Patricia Hennessey's burned-out Jeep

The bodies of both Nash Campbell and Patricia Hennessey were identified by dental records and a DNA match, respectively. (RCMP)

One police officer told the inquest he couldn't believe what he was seeing when he looked into the vehicle. What he thought at first was a teddy bear was Nash's body lying beside his mother.

Later Dr. Matthew Bowes, chief medical examiner for Nova Scotia, testified, saying it was his conclusion that Nash and Hennessey were both sedated and died of smoke inhalation. He said he believes it was a murder-suicide.

The bodies were so badly burned that Hennessy had to be identified by dental records and Nash by a DNA match with his mother, said Bowes.

The inquest itself started late Monday morning because it had to be determined whether a publication ban would be instituted. After hearing from lawyers on both sides of the argument, Montgomery ruled against granting the ban, saying courts are based on an open process and agreeing there is public interest in the case.

The inquest is expected to last until this Thursday. It will then adjourn until March 30 to hear from an expert witness on domestic violence who is unavailable this week.