(NewsNation) — The Justice Department is suing Southwest Key Programs, the nation’s largest housing provider, for an alleged pattern of sexual abuse against unaccompanied migrant children in its shelters.

The lawsuit claims Southwest Key employees, including supervisors, engaged in over 100 instances of sexual abuse and harassment spanning at least eight years. Allegations include rape, solicitation of sex and requests for nude images from children as young as five.

Southwest Key, a national nonprofit, operates 29 shelters across Texas, Arizona and California, with its largest facility in Brownsville, Texas, housing up to 1,200 children.

Carlos Arellano, a former contractor for Southwest Key, told NewsNation he heard reports of abuse from children in the organization’s care. Arellano raised concerns about missing children and the organization’s hiring practices.

The DOJ alleges that employees exploited children’s vulnerabilities, threatening them to maintain silence and taking advantage of language barriers and separation from family. The organization is accused of failing to prevent sexual harassment, not following federal abuse reporting requirements and discouraging children from disclosing incidents.

Southwest Key disputes the allegations.

In a statement, the organization said, “The allegations are deeply disturbing and we are committed to fully cooperating with the investigation while maintaining the highest standards of care and safety for the children in our programs.”

The lawsuit seeks monetary damages for the affected children.