(CNN) -- The uncle of a 12-year-old Vermont girl whose body was found Wednesday was charged with kidnapping, a federal prosecutor said Thursday.
An autopsy was taking place Thursday on the body of Brooke Bennett, and the suspect, Michael Jacques, could face further charges if the death is ruled a homicide, U.S. Attorney Thomas Anderson said.
A kidnapping that results in a death is potentially a capital crime, Anderson said, and the suspect could face execution or life in prison even without being charged in the killing of his niece.
Jacques was arrested Sunday on a charge of sexually assaulting another young girl, according to an affidavit filed in U.S. District Court in Burlington, Vermont.
Ray Gagnon, Brooke's former stepfather, has been charged with sexually assaulting the same child. Gagnon also faces a federal obstruction of justice charge and is due in court Monday. Watch authorities announce the charges »
Brooke's body was found in a fresh grave off a road in Randolph, a town about 60 miles southeast of Burlington, a week after she disappeared.
"It appears to be foul play," Col. James Baker, director of the Vermont State Police, said Wednesday.
Information gathered in a search of Jacques' home led police to the grave site, Baker said, but he provided no details.
The girl Jacques is accused of assaulting told detectives that he had been having sex with her since she was 9, according to the affidavit. She also told investigators she had a sexual encounter with Gagnon in June 2007, the affidavit said.
The girl recounted how when she was 9 she found a note under her pillow that said she had been chosen to be in a program for sex called "Breckenridge," the affidavit said. She was told that her "trainer" was Jacques. She told authorities that to graduate she had to attain a 75 percent on "how you perform."
According to the affidavit, the girl said Jacques picked Brooke up on June 25 and told her they would be going to a party. The girl told police she understood Brooke would be "taken into the 'Breckenridge' program that day, and that she would have sex with adult males."
The girl said that she, Brooke and Jacques then went to Jacques' home, where the two girls watched television until the man asked Brooke to come upstairs with him. The girl said she never saw Brooke again and that Jacques ordered her to lie about what happened that day, according to the affidavit.
Asked Thursday if a ring of child abusers is at large, Anderson said he did "not believe there was a continuing danger to the public."
Vermont Attorney General William H. Sorrell added, "There's nothing from this investigation that's been turned up, nor otherwise are federal and state authorities aware of any ongoing efforts to recruit young girls or boys here in Vermont to have sex with adults."
In court papers, federal agents said Gagnon, 40, of San Antonio, Texas, admitted he had sex with the second girl and keeps child pornography on his computer.
Jacques told state police that Brooke's computer postings indicated that she planned to run off with someone she met online, and he showed detectives a message he said supported that belief, according to the affidavit.
But investigators believe the posting was written "to make it appear that [Brooke] was abducted by someone she met on the Internet," the affidavit said.
Changes to the message had been made by a computer at the Texas home where Gagnon rents a room, the affidavit said. The home's owner told investigators that Gagnon had called him Monday and told him to get rid of his safe -- which the owner assumed contained child pornography, according to the affidavit.