The 196-count indictment, announced by the U.S. Attorney's Office, follows earlier state charges against four of the defendants and alleges the captors held adults with disabilities in subhuman conditions in order to carry out Social Security fraud.
Linda Ann Weston, 52, who police have described as the ringleader of the alleged fraud and abuse scheme, her daughter, Jean McIntosh, 33, Gregory Thomas, Sr., 49, Eddie Wright, 52, and Nicklaus Woodard, 26, are accused of using isolation, intimidation, threats of violence and violence to control the victims and each defendant had a role in the racketeering enterprise, according to the indictment.
Additional charges in the federal indictment include murder in aid of racketeering, kidnapping, forced human labor, theft and fraud.
The investigation into Weston and her alleged co-conspirators began when the four mentally disabled adults were found in October 2011 locked in the sub-basement room with no food and only a bucket for a toilet.
According to the indictment, the defendants beat the victims, kept them captive in locked closets, basements and attics, deprived them of adequate food and medical care, and moved them between Pennsylvania, Texas, Virginia, and Florida in order to further the scheme and evade law enforcement.
The defendants also are charged with violating the Matthew Shepard and James Byrd Jr. Hate Crimes Prevention Act -- which criminalizes violence motivated by any person's actual or perceived disability, race, color, national origin, religion, sexual orientation, gender, or gender identity -- for their alleged actions against the disabled victims.
"The physically and mentally disabled are among the most vulnerable in our society. They deserve to be treated with respect and compassion, not violence," U.S Attorney Zane David Memeger said in a statement. "Linda Weston and others, in fact, decided to prey on these victims specifically because of their physical and mental challenges and they did so through violence, fear and intimidation for the purpose of stealing Social Security payments that were meant for the victims' long-term care."
As the first hate crimes case of its kind because the victims were disabled, the indictment alleges that Weston's "abusive control and confinement techniques" caused the deaths of two of the victims, including Weston's former roommate, Maxine Lee, who she allegedly continued to collect benefits from after she died of acute meningitis.
The medical examiner said a contributing factor in Lee's death was "cachexia of unknown origin," or malnutrition. The manner of death is listed as "natural causes."
"Shocking does not begin to describe the criminal allegations in this case where the victims were tied up and confined like zoo animals and treated like property akin to slaves," Memeger said.
The four mentally disabled adults held captive -- Edwin Sanabria, Herbert Knowles, Tamara Breeden and Derwin McLemire -- were locked in a pitch-black, 13-by-7 foot room that housed the former boiler used to heat the building, police said.
A penetrating stench of urine and feces still hung in the chamber days after the discovery. McLemire had been chained to the boiler, police said.
"I used the bucket to go to the bathroom. Others used the same bucket," Sanabria testified last January at hearing where a judge ordered the case to go to trial. When asked where he took a bath, he said they "used the same bucket we used to urinate in."
The investigation took several bizarre twists as authorities tried to piece together the evidence in the case, which has spread to at least two other states after detectives discovered that one of the accused had traveled across state lines with the people found in the boiler room.
"Today's Indictment represents just one more step towards closure and healing, not only for the victims of this heinous hate crime, but for the community as a whole," FBI Special Agent-in-Charge John Brosnan said in a statement.
If convicted of all federal charges, each of the defendants faces a statutory maximum sentence of life in prison. Weston potentially faces the death penalty and mandatory restitution of approximately $212,000.
Due to the federal charges, the state plans to withdraw its charges against Weston, Thomas, Wright and McIntosh, according to the district attorney's office in Philadelphia. They were scheduled to go on trial January 28.
Weston's attorney was not immediately available for comment.