Police on Tuesday were searching for two young children and their parents, who allegedly kidnapped the youngsters at gunpoint from their foster home.

An Amber Alert (search) was issued Saturday for James Paul Chambers, 2, and his sister, Breanna, 11 months.

Authorities said their father, James Lee Canter (search), 28, a fugitive on a drug charge, brandished a gun when he and their mother, Alisha Chambers, 18, took the children from a foster home in the Valle Crucis area early Saturday.

The couple were spotted that same day just over the state line in Johnson County, Tenn., but Tennessee authorities found only their car, containing a rifle and a handgun, Watauga County Sheriff Mark Shook said.

The FBI was assisting because the couple crossed state lines, Shook said Tuesday.

The county social services agency took custody of the children after a raid last March on the couple's remote home, where authorities said they discovered a methamphetamine (search) lab.

Canter has been a fugitive since the raid. Chambers was arrested at the house and charged with manufacturing meth and maintaining a dwelling for its manufacture. She posted bail about two months later.

Rosalee Canter, who said she raised her grandson James Canter until he was 9, said Monday she didn't know where he was.

"I know wherever he is, he's taking care of those young 'uns," she said. "But I'd think there's a better way to go about taking your kids."

Because of the wintry cold in the mountains along the Tennessee line, authorities doubted that the family was on foot since they left behind the car.

"We strongly believe somebody's helping them: family, associates," Maj. Paula Townsend of the Watauga sheriff's office told The Charlotte Observer. "Somebody had to have picked them up."