US authorities on Wednesday announced hate crime charges against a gang accused of imprisoning mentally disabled people in a decade-long scheme to steal their Social Security benefits.

The charges marked the first time authorities have applied a federal hate crime statute signed by President Barack Obama to a case involving the disabled, rather than ethnic or sexual minorities.

"The physically and mentally disabled are among the most vulnerable in our society. They deserve to be treated with respect and compassion, not violence," said the federal prosecutor, US Attorney Zane Memeger.

In addition to hate crime charges, Linda Ann Weston, her daughter, boyfriend and two others face allegations of murder, sex trafficking, kidnapping, forced human labor and racketeering against six disabled adults and four children.

The scheme was uncovered in October 2011 when a landlord found four adults aged 29 to 40 chained behind a steel door in a filthy, dirt-floor Philadelphia basement.

Philadelphia police say Weston and her accomplices traveled across the country with her captives, moving to Texas, Florida and Pennsylvania to avoid discovery.

According to the US Attorney's Office, Weston persuaded mentally challenged individuals to name her as their caretaker, a move that allowed Weston to collect their benefits checks.

Weston then controlled every aspect of their lives, offering abysmal diets, forced housework and beatings if they tried to escape.

Two individuals died in her care, authorities say. Two others were forced to work as prostitutes. Their diets consisted of one meal per day -- often rice, beans or noodles.

Weston faces the death penalty, although authorities have not decided whether to seek it.

The four other defendants -- daughter Jean McIntosh, 33; boyfriend Gregory Thomas, 49; Eddie Wright, 52; and Nicklaus Woodard, 26 -- face life in prison.

After federal prosecutors announced charges, the local District Attorney's office announced it would drop its own case. Weston, Thomas, Wright and McIntosh had all faced trial in Philadelphia on January 28.