Almost 5,000 complaints of sexual abuse and harassment of migrant children in US custody have been filed over the past four years, according to government documents released this week. The allegations range from adult staff members having relationships with minors, and the showing of pornographic videos, to forcible touching.

According to Department of Health and Human Services (HHS) documents released on Tuesday on Capitol Hill by the Florida Democratic representative Ted Deutch’s office, the reports date back to October 2015, during the Obama administration. However, most of the sexual abuse and harassment reported occurred since Donald Trump took office.

During a House judiciary committee hearing on Tuesday, Deutch addressed the documents and linked them to the Trump administration’s “zero-tolerance” policy on immigration, regarding unlawful incursions of the US-Mexico border. The policy, widely regarded as a strong-arm attempt by the government to discourage immigration, resulted in almost 3,000 migrant children being forcibly separated from their families.

“These documents tell us that there is a problem with adults, employees of HHS, sexually abusing children,” Deutch said at the hearing.

The total number of sexual abuse complaints in 2018 was 1,261, an increase of 192 compared with 2017. While the majority of the sexual assaults were allegedly committed by other minors in custody, 178 out of the thousands of complaints filed were accusations against staff. The number of reported sexual abuse incidents involving staff against migrant children increased in 2018, with a total of 12 complaints filed in July compared with four in February.

“This works out, on average, to one sexual assault by HHS staff on an unaccompanied minor per week,” Deutch said. The point was angrily disputed by Jonathan White, a testifying official who has overseen child migrant detention matters at HHS.

He questioned whether the staff members involved in the allegations were members of HHS staff or affiliated to outside contractors.

“Those are not HHS staff in any of those allegations,” White said.

White also stated that when a sexual assault is reported, it is fully investigated. Reports deemed legitimate are then sent to the Department of Justice for prosecution, he said.

The Department of Justicereceived 29% out of the total of 4,556 reports initially filed, according to the data released by Deutch’s office.

HHS manages the care of tens of thousands of migrant children, most of whom had crossed the border alone. However, in August 2017, 3.6% of the children had been separated from a parent or a guardian. After they are detained at the US border by Customs and Border Protection (CBP), they are placed in privately run shelters contracted by the government.

Officials say most of the allegations haven’t been substantiated and are defending the care they provide to immigrant children.

However, reports of sexual assault against minors are not the only tragedies coming out of the US detention facilities. Two Guatemalan children have recently died under US custody, shining light on the treatment of immigrants detained by authorities.