Two weeks after a 3-year-old boy from Caroline County, Va., disappeared in the care of his mother's boyfriend, the man has been charged with second-degree murder.

Tyreek Davis has not been seen since Sept. 29, and authorities would not say yesterday what evidence they have that the toddler, the youngest of four siblings, is dead.

In announcing the charge against Herman L. Black, however, Spotsylvania County Sheriff Howard D. Smith said Black, 45, had revised his account of Tyreek's disappearance at least three times. Smith would not elaborate.

Smith indicated that the murder charge, which was filed Wednesday, was not based on Black's new account. "He would have been charged anyway," Smith said.

Initially, Black told police that he left Tyreek, sleeping and unattended, in a truck outside a Fredericksburg Wal-Mart in the afternoon and that the boy was gone when he returned. A few days later, Black, who runs a woodcutting business, said that he left the boy in the woods in the morning when he went to do errands and buy drugs and that he had forgotten him. Helicopters, dogs and hundreds of people searched both areas without finding the boy.

Smith said the FBI has finished forensic tests on a van, a log splitter and two trucks, at least one of which belonged to Black's company. In seeking a search warrant for Black's 1989 brown GMC pickup, Fredericksburg police said in the affidavit that they were looking for evidence, such as bodily fluid, that could be tested for DNA.

But the city police, who initially handled the case when it appeared that the child had been abducted from the parking lot, said they knew of no "hard evidence" against Black that had turned up in the investigation.

"It was more the story and the facts as he tried to describe them. It just didn't add up," city police spokesman Jim Shelhorse said.

Black has been in jail since the day Tyreek disappeared, when police realized that Black was wanted on unrelated weapons charges. He was arraigned yesterday on the murder charge -- via video -- in Juvenile and Domestic Relations Court. Calls to the public defender's office, which is representing him, were not returned.

Tyreek's mother, Lynette Davis, and her family declined to comment yesterday. They initially said they were sure Black would never hurt the boy, for whom he often baby-sat.

Davis, 29, said that she had been with Black for about a year, and that she had been living with him and her four children in a Caroline County motel for about a month while they looked for a home. Davis, who is from Caroline, has siblings in the area.

Authorities have said Davis is not a suspect. Smith said yesterday he did not expect anyone else to be charged.

Black's brother, who lives in Spotsylvania, did not return calls yesterday.

Tyreek's disappearance has absorbed the area since he vanished, with most store windows displaying posters of his face and the sheriff's department's phone number.

Dozens of people joined in the first search, which began Sept. 30 and lasted less than two days. Police halted that search because they said they were distrustful of Black's first account and weren't convinced that the boy had been abducted. Four days later, the search was renewed after Black said he mistakenly left the boy in the woods.

Smith said yesterday he didn't know where the boy's body is or what had happened.

"We couldn't have charged him with murder if we didn't know [Tyreek] was dead. But [Black] has told us three different stories; we don't know what to believe from him," Smith said. "And we won't believe anything from him until we find the child."

Smith said his deputies are investigating 70 leads. A preliminary hearing for Black is scheduled for Jan. 26.

Herman L. Black is charged with second-degree murder in the disappearance of Tyreek Davis, who was last seen Sept. 29.A military helicopter equipped with a thermal imaging sensor aids the ground search for Tyreek Davis last week in Spotsylvania County, Va.