What to Know
Police say a 15-year-old Florida boy was detained while trying to cross the New York-Canada border Saturday
The teen is a person of interest in the death of his 53-year-old grandmother
He was on the run for three days in her stolen car and was believed to be armed and dangerous with guns taken from his father's arsenal
A Florida teenager trying to enter Canada has been detained by U.S. border patrol agents who want to interview him in connection with the death of his grandmother.
The Jacksonville Sheriff's Office said at a news conference late Friday that the 15-year-old was stopped near Buffalo, New York.
Officials in Florida started looking for the boy and his 53-year-old grandmother on Wednesday after the two of them failed to pick up the teen's father at the airport.
The father had been on vacation with his girlfriend. His mother was watching her grandson while they were gone.
When the father got to his home in Neptune Beach, near Jacksonville on Florida's Atlantic coast, he found it had been ransacked. His mother's home in nearby Mayport was also ransacked. Weapons were missing from both homes and the grandmother's 2015 Dodge Dart was also gone.
Officials said at the news conference that the father is a corrections officer for the Jacksonville Sheriff's Office.
Ron Lendvay, a director of investigations and homeland security for the sheriff's office, said surveillance footage from a gas station in south-central Pennsylvania picked up the image of the teen and Dodge Dart on Thursday afternoon.
Lendvay said a warrant was issued for the teen's arrest on an auto theft charge.
Earlier Friday, officials said a body that matched the grandmother's description was found in a shallow grave in the teen's backyard. Officials are waiting for an autopsy but the teen's mother said the body belongs to her ex-husband's mother Kristina French.
Carrie Campbell-Mott, who is divorced from the teen's father, told NBC News that the boy had a loving relationship with his grandmother.
"He has a really big heart. He has never said a bad word to anybody. So it's just baffling," Mott said.
She said her son's diabetic son's mechanical insulin pump recently stopped working — an imbalance in blood sugars has caused erratic behaviors before.
But medical doctors say violence linked to high blood sugar levels is rare.
Campbell-Mott said her son loves the outdoors and is an avid survivalist.
"My gut tells me that he just ran. Like his only thought was to panic and run and to take the guns and go to the woods," she said.