One of two young boys allegedly abducted by their father at knifepoint was found dead in a lake, and his brother and father were pulled from the water with knife wounds, authorities said Wednesday.

Katron Walker, 32, was charged with murder and attempted murder, said assistant chief of detectives Bill Bergherm. He said Walker had stab wounds in his chest but was expected to survive.

The youngest boy, 2-year-old Monte, was hospitalized in good condition with cuts on his neck and puncture wounds in his chest, Bergherm said.

Collin, 4, was found dead late Tuesday by police divers in the lake just south of Terre Haute. The child's throat had been cut and he had been stabbed in the chest, Bergherm said.

An Amber Alert had been issued for the boys earlier Tuesday, after police say Walker abducted his sons at knifepoint from their grandfather's backyard amid a custody dispute.

Police found Walker's van at the private lake in Blackhawk that evening.

While police were searching the area with dogs, Walker ran out of an abandoned trailer and jumped into the water with the children in his arms, Bergherm said.

Officers jumped in after them and grabbed Monte, but they couldn't find Collin in the dark, murky water, he said. The dive team found the body in about 12 feet of water.

A woman who lives near the lake told police she had seen the three earlier in the day fishing and eating hot dogs.

The boys' mother, Teresa Walker, said she had called her husband from work that day to say she wanted a divorce. Shortly after the call, Katron Walker showed up in the yard wielding a knife and took the boys, said Michael Dwyer, the boys' grandfather.

"My sister went out and she was trying to get them back," Dwyer said. "He threw her down and she came right back at him and he kicked her twice in the chest."

Katron Walker was under police guard Wednesday at a hospital where he was being treated for wounds that police say were self-inflicted. Police said he had marijuana and methamphetamine in his system.