MONCKS CORNER, S.C. (AP) — A man and his girlfriend were charged Thursday in the death of a toddler whose remains were found buried in 400 pounds of concrete in a trash can, after police said the couple concocted a story about the child falling into a river near a popular tourist destination.

Roger Williams, 29, and Grace Nichole Trotman were charged with homicide by child abuse after an autopsy revealed the concrete held the body of a young black boy matching a description the couple had given Charleston police for Williams’ missing son, Berkeley County Sheriff Wayne DeWitt said.

Investigators were awaiting the results of a DNA test to confirm that the boy found in the bin was Rodricus Williams, who police think was killed at a Berkeley County home and whose death was revealed only when Rodricus’ mother wanted to visit him unexpectedly.

DeWitt could not say how long the boy had been dead. “We do know days, maybe longer,” he said.

Police said the boy had been staying with Williams and Trotman, and when Rodricus’ mother called wanting to see the child, she was told she could pick Rodricus up Tuesday at the Battery in Charleston, a popular tourist destination and Civil War site on the city’s peninsula.

The couple then reported the boy had fallen from the Battery into Charleston Harbor, touching off a more than 10-hour search by police and rescue workers on foot and by boat. “It was a concocted story,” DeWitt said.

Trotman has been charged by Charleston police with filing a false report.

Trotman has been cooperating with police while Williams has given investigators false information, DeWitt said.

Officials did not immediately know whether the two had attorneys, though Williams had stopped speaking with police and asked for a lawyer, DeWitt said at a news conference.

“She is still being cooperative,” DeWitt said. “Mr. Williams has refused to answer any questions.”

Police have said that interviews with Trotman and Williams led them to the bin just off Interstate 26 in Orangeburg County in central South Carolina, some 55 miles northwest of Charleston. Because of the weight of the container, a farmer was asked to hoist it onto a county vehicle using a backhoe. The bin was disassembled and the remains examined Thursday at the Medical University of South Carolina in Charleston.

DeWitt said the boy’s body was inside 32-gallon trashbags and the concrete was poured on top. He said investigators think the boy was dead before he was put in the bin, which was located behind an abandoned mobile home in a rural area surrounded by small homes and cornfields.

Copyright 2010 The Associated Press.