A massive explosion that decimated a Mississauga house and destroyed several others was intentionally sparked as part of a double suicide, Peel Regional Police confirm.

The blast, which occurred on June 28, levelled the house located on Hickory Drive and destroyed several other homes.

Two people – 55-year-old Dianne Page and her husband, 55-year-old Robert Nadler – were killed as a result.

The explosion, which sent heavy debris flying hundreds of metres from the blast zone, prompted officials to issue an evacuation order that initially impacted 700 addresses in the surrounding area, located near Dixie Road and Rathburn Road East.

At a press conference late Friday afternoon, Peel Regional Police Chief Jennifer Evans said that after “a very comprehensive investigation” investigators determined that the blast was part of a double suicide and caused by a severed natural gas pipe.

“Police investigators have identified four possible scenarios which may have caused the explosion. Each scenario has been thoroughly investigated,” she said.

“This investigation determined that the explosion was intentional and given the supporting evidence, it has ruled out accidental, double murder or murder suicide.”

A post-mortem examination on Page and Nadler determined their cause of death to be blunt-force trauma “consistent with having been near the epicenter of the explosion.” A pathologist was unable to determine where exactly the victims were located in the home when the blast took place, nor their proximity to the source of the ignited gas.

Investigators with the Ontario Fire Marshal (OFM) determined that the explosion originated in the basement of the home where a natural gas pipe was intentionally disconnected from a hot water tank in two places.

“Due to the low ignition energy of natural gas, an ignition source could not be isolated,” Kevin Pahor, an investigator with the OFM, told reporters at the news conference.

“Once the natural gas enters its explosive range, any ignition source – ranging from an electrical circuit to an occupant using an open flame – could have ignited the natural gas and thus causing the explosion.”

Lahore said investigators couldn’t calculate how long the house had been filling up with gas due to the level of damage caused to the home by the explosion.

But Det. Raj Klair, with Peel Regional Police 12 Division, said that Page and Nadler were “both alive prior to the explosion” and had “ample opportunity to exit the residence” upon smelling any gas.

“We’ve had witnesses indicate they were able to smell gas about an hour-and-a-half prior to the explosion,” he said.

“Any individual that was inside the residence, the two individuals, would have easily been able to smell the gas and, had they wanted to exit, would have had that opportunity.”

Notes found at home may be from victim

As the dust settled over the debris on that June afternoon, a large number of hand-written notes were found nearby. Sources told CTV News Toronto back in July that the notes appeared to be written by someone who was in some form of distress.

Klair said the notes underwent a handwriting analysis and were determined to be written “mostly by one person.” Though the analysis was unable to establish the person who wrote the notes, Klair said that, “based on the context of the notes,” they appeared to have be written by Page.

“The notes that were found indicated a state of mind which was consistent with someone suffering from some sort of depression,” he said. “Though we’re not sure if they had anything to do with the explosion.”

Klair said one witness told investigators that Nadler indicated that he and Page were suffering from cancer and “didn’t have long to live” but toxicology reports did not find any history of cancer in either victim.

Sources also told CTV News Toronto back in July that Nadler was convicted of murdering his friend over money in the 1980s.

Chief Evans confirmed Friday that Nadler was convicted in 1982 and served nine years for the crime. She said he was on parole when the explosion levelled his home in Mississauga.

“From all indications, he was complying with parole conditions,” she said. “I can tell you we had no contact with Mr. Nadler following that 1982 homicide.”

Many residents still displaced after blast

Mississauga Mayor Bonnie Crombie confirmed 33 residences in the neighbourhood remain empty. She said the city “remains engaged” with the residents impacted by the destruction and intends to continue offering support to those in need through the holidays.

“It’s certainly a tragedy for everyone involved. I want to thank the first responders who were so brave and acted so professionally,” she said. “We feel for those 33 families who are still out of their homes and we are working with them to insure that they can get back or rebuild their homes at their earliest convenience.”

She said that those impacted by the incident will be notified of another community meeting where residents can have more questions answered. Representatives from insurance agencies are expected to be on hand at the meeting as well.

It was not clear when or where the meeting will be held.