Brooke Bennett, of Braintree, disappeared June 25 and was found dead a week later. Her disappearance triggered Vermont's first-ever Amber Alert, and state residents were shocked when her body was found in a shallow grave July 2.
Other charges against Jacques, 42, of Randolph, in the indictment announced Wednesday include five child pornography counts.
Two of Jacques' lawyers - public defender Michael Desautels and death penalty expert David Ruhnke - didn't return telephone calls seeking comment on the indictment.
Jacques has been in custody since before the girl's body was found, but the indictment contained new details about the slaying.
Jacques allegedly persuaded the second girl, identified only as "J1," to help kidnap Brooke by sending messages saying that Brooke had been "designated for termination," falsely telling the girl that Brooke "was causing significant problems for J1's father, resulting in him becoming suicidal."
The indictment said Jacques told J1 about a child-sex club called Breckenridge - a nonexistent group that Jacques allegedly made up to coerce her into sex for years and to get her to help with Brooke's abduction.
Beginning in 2003, Jacques "intimidated, deceived and persuaded a nine-year-old girl (J1) into believing that a powerful organization named 'Breckenridge' would harm or kill her and her family if she did not engage in sex acts with" him, U.S. Attorney Thomas Anderson said in news release.
Between 2003 and 2008, Jacques caused J1 to engage in sex acts that he videotaped and shipped in interstate commerce, the indictment said.
It said he used fake e-mail, text and other messages to convince J1 that she was hearing from Breckenridge operatives and "that on occasion, Breckenridge 'terminated' girls. J1 was informed that, while she would not be required to participate in such a termination, she might be required to assist in related planning."
Such assistance was required in May and June of this year, the indictment said, when Jacques ordered J1 to help him plan Brooke's abduction by convincing Brooke that she would be attending a pool party at Jacques' house.
According to the indictment:
Anderson said it would be up to U.S. Attorney General Robert Mukasey whether prosecutors seek the death penalty against Jacques. That decision "is not expected for several months," which could leave it up to the attorney general of a new presidential administration.
Brooke's disappearance and death has triggered calls by the public and political leaders for toughening Vermont's sex offender laws.
Her father, James Bennett, of Bethel, didn't immediately return a call seeking comment Wednesday.
Also Wednesday, Anderson said federal authorities have dropped an obstruction of justice charge against Raymond Gagnon, 40, the girl's former stepfather - a charge lodged in connection with her disappearance.
Gagnon, of San Antonio, has been indicted by a federal grand jury in Texas on charges of production and transportation of child pornography.