House Explosion Mt Joy Twp.

Aftermath of an apparent house explosion on Waldheim Road in Mt. Joy Twp. Tuesday June 1, 2021.

Editor’s Note: This story has been updated with information released by Northwest Regional Police on Thursday, July 8, 2021, and in interviews, Friday, July 9.  

A month after two bodies were found inside the remains of a Mount Joy Township home explosion, police have ruled their deaths murder-suicide. 

The bodies of David Preston, 63, and Victoria Preston, 60, were found in their home in the 100 block of Waldheim Road after an explosion early on the evening of Tuesday, June 1. 

Police determined David Preston killed his wife by giving her toxic levels of prescription drugs, including fentanyl, before setting the house on fire using some sort of a flammable substance. 

Here is a look at what we know and don't know. 

Who were the Prestons? 

According to their obituaries, David was born in Munich, Germany, and worked as an engineer in the aeronautics industry and Victoria, who was born in Mineola, New York, had been a DJ. They both served in the Navy. 

LuAnn Gantz, of Mount Joy, said was good friends with Victoria for about a half-dozen years and knew David, too, although she had not seen them for a while.

“They were both very nice, very friendly. They were quiet and kept to themselves,” Gantz said Friday. The couple had children, Gantz said, but she had never met them. Their obituaries did not list next of kin.

Gantz met Victoria Preston about a half-dozen years ago, perhaps a bit longer, when Preston was driving a van to pick up international students, which both families hosted.

Gantz declined to talk about Victoria Gantz’s medical condition.

Northwest Regional Police Chief Mark Mayberry said the detective who handled the case was off Friday, but that he knew Victoria Preston did have a prescription for pain medication, but he did not know what the prescription was for, nor her medical condition.

When were the explosions reported? 

Emergency crews were dispatched at 5:57 p.m. Tuesday, June 1, to a residence in the 100 block of Waldheim Road, just off of Mt. Gretna Road (Route 241) northeast of Elizabethtown, following reports of an explosion that set a home there on fire. 

A dispatcher told LNP at the time that firefighters arrived to find the house on fire and live wires on the ground. 

Property records indicate the residence was a 2,240 square-foot rancher built in 1972. 

What did neighbors hear? 

Neighbors reported hearing one large explosion, followed by several other smaller explosions. They also reported hearing what appeared to be ammunition exploding after the initial explosions rang out. 

Keith Mapplebeck, 52, who lives around the corner on Mount Gretna Road, was in his yard when he heard what he described as a single, massive explosion. 

“It was a huge boom,” he said. 

Mapplebeck, who shoots live cannons as part of pirate reenactments, said the explosion was louder than anything he’s ever heard, shaking the ground like an earthquake.

What caused the explosion? 

On July 8, police concluded that the house exploded as a result of a fire intentionally set by David Preston after he killed his wife using prescription medications. 

Police did not provide any other details of how the fire led to the explosion. 

What happened to the Prestons before the explosion? 

David Preston killed Victoria Preston by giving her toxic levels of fentanyl and other prescription medications, police said. He then ignited a flammable substance “on our around his body and throughout the residence.” 

Police did not specify what sort of substance David Preston used. 

What were the Prestons’ cause and manner of death? 

Victoria Preston died as a result of toxic levels of fentanyl and other medications, police said. Police also determined she was dead at the time the house was set on fire by David Preston. 

David Preston died as a result of “extensive smoke and thermal injuries, both internal and external,” police said. 

The manner of their deaths was a ruled a murder-suicide. Dr. Stephen Diamantoni said that determination was made by testing the CO2 levels in the Prestons’ blood and lungs. Victoria Preston’s blood did not have high levels of CO2, but did have a high concentration of drugs in her system, which Diamantoni said indicates she died before the fire. 

David Preston, however, had high levels of CO2 in his system, but no high level of drugs, Diamantoni said.

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