~ Capital murder: Lam Luong was charged in the deaths of his children.

BAYOU LA BATRE, Ala. -- A day after reporting his four young children were missing, a shrimp fisherman broke down and confessed that he threw them off an 80-foot-high bridge to their deaths, authorities said Wednesday.

Lam Luong, 37, was charged with four counts of capital murder, and divers searched the murky waters for the bodies of the youngsters, who ranged in age from a few months to 3 years.

Luong had a drug habit and had argued with his wife, Ngoc Phan, before taking the children, said Phan's brother-in-law, Kam Phengsisomboun.

Luong's girlfriend, who was living in a hotel in nearby Gulfport, Miss., was a factor in the couple's argument Sunday and Monday morning, family members and police said.

Authorities said they believe Luong then drove to the two-lane Dauphin Island bridge over the Intracoastal Waterway on Monday, stopped at the highest part of the span and threw the youngsters over the side.

Luong reported the children missing Monday, initially telling police that he had given the children to his girlfriend, and that she failed to return them.

But authorities said they found holes in his account, and he later changed his story.

Missing and presumed dead were 4-month-old Danny Luong; 1-year-old Lindsey Luong; 2-year-old Hannah Luong; and 3-year-old Ryan Phan. Phan is not the man's biological child, but Luong raised him from infancy, authorities said.

About 70 people in boats and helicopters searched water as deep as 55 feet. The search area covered 100 square miles because the current might have swept the children away, Sheriff Sam Cochran said.

The search was called off late Wednesday afternoon when dense fog rolled in, completely obscuring the bridge.

Luong is scheduled to appear in court today. District Attorney John Tyson said he did not believe Luong had an attorney.

Luong came to Alabama from Vietnam in 1984 and worked as a shrimper, Phengsisomboun said. The couple lived with Phan's mother at Bayou La Batre, a fishing village 20 miles southwest of Mobile with a large Southeast Asian community.

Phengsisomboun said the couple had recently moved back to the area from Hinesville, Ga.

The family initially feared Luong had traded the children to support his drug habit, Phengsisomboun said. Luong had a crack habit and had run through an insurance settlement from an auto accident, he said. Authorities in Mobile confirmed Luong had a history of drug abuse but had no details.

He was arrested in October in Hinesville on a crack-possession charge. The case has not been acted on by a grand jury.

Phengsisomboun said he was later told by investigators that a witness had seen someone throw a bundle from the bridge and then saw three children in a nearby car.

Phan, 23, was in seclusion Wednesday morning at her mother's brick home, the front porch cluttered with children's shoes.

Some family members and friends held out hope that the children weren't dead.

"I just pray for the kids, that they are still alive," said Van Lam, a family friend who was at a market with Phan's mother Wednesday afternoon.