AUSTIN, Texas (AP) — The largest housing provider for unaccompanied migrant children has engaged in the “severe, pervasive” sexual abuse and harassment of children in its care, the Justice Department alleges.

Southwest Key employees, including supervisors, have raped, touched or solicited sex and nude images of children in its care since at least 2015, the DOJ alleged in a lawsuit filed Wednesday. At least two employees have been charged since 2020, according to the lawsuit.

Based in Austin, Southwest Key is the largest provider of housing to unaccompanied migrant children, operating under grants from the U.S. Department of Health and Human Services. It has 29 child migrant shelters: 17 in Texas, 10 in Arizona and two in California.

Children living there range in ages from 5 to 17. Among the allegations is the repeated abuse of a 5-year-old in the care of a Southwest Key shelter in El Paso. In 2020, a youth care worker at the provider’s Tucson, Arizona, shelter took an 11-year old boy to a hotel for several days and paid the minor to perform sexual acts on the employee, the Justice Department alleges.

Children were threatened with violence against themselves or family if they reported the abuse, according to the lawsuit. It added that testimony from the victims revealed staff in some instances knew about the ongoing abuse and failed to report it or concealed it.

Health and Human Services Secretary Xavier Becerra said Thursday that the complaint “raises serious pattern or practice concerns” about Southwest Key. “HHS has a zero-tolerance policy for all forms of sexual abuse, sexual harassment, inappropriate sexual behavior, and discrimination,” he said in a statement.

The lawsuit comes less than three weeks after a federal judge granted the Justice Department’s request to lift special court oversight of Health and Human Services’ care of unaccompanied migrant children. President Joe Biden’s administration argued that new safeguards rendered special oversight unnecessary 27 years after it began.

The Associated Press left a message with the company seeking comment Thursday.