(CNN) -- The uncle of a 12-year-old Vermont girl whose body was found Wednesday will face federal kidnapping charges, the U.S. attorney for the district of Vermont announced Thursday.
An autopsy is taking place Thursday and the suspect, Michael Jacques, could face further charges if the death of Brooke Bennett is ruled homicide, U.S. Attorney Thomas Anderson said.
Brooke's remains were found Wednesday afternoon in a fresh grave off a road in the town of Randolph, about 60 miles southeast of Burlington, Vermont.
"It appears to be foul play," said Col. James Baker, the director of the Vermont State Police.
Jacques was arrested Sunday on a charge of sexually assaulting another child, also identified in a police affadavit as a relative of Jacques.
That girl told police about her association with Brooke, Jacques and an alleged child sex ring. Information gathered in a search of Jacques home led police to the gravesite, Baker said, but he provided no details.
An affidavit filed in U.S. District Court in Burlington states that Jacques, 42, dropped Brooke off at a convenience store in Randolph on June 25. He told investigators that his niece was to be picked up by a friend later to visit a sick relative.
The relative Jacques is accused of assaulting told detectives that he had been having sex with her since she was 9. She also told investigators she had a sexual encounter with Brooke's former stepfather, Ray Gagnon, in June 2007.
According to the affidavit, 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." 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 same 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 stated that she, Brooke and Jacques then went to Jacques' home where the two girls watched television until Jacques asked Brooke to come upstairs to be 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. Watch press conference announcing the discovery of the body »
Gagnon, 40, of San Antonio, Texas, is also charged with sexually assaulting a minor, as well as a federal obstruction of justice charge. In court papers, federal agents say Gagnon admitted to having sex with the same girl Jacques is accused of assaulting and to keeping child pornography on his computer.
Jacques told state police that Brooke's computer postings indicated she planned to run off with someone she met online, showing detectives a message he said supported that belief.
But investigators believe the posting was written "to make it appear that (Brooke) was abducted by someone she met on the Internet," the affidavit states.
Changes to the message had been made by a computer at the Texas home where Gagnon rents a room, the affidavit states. 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.