▶ Watch Video: Biden administration begins reuniting some migrant children with their parents

The Trump administration deported at least 348 migrant parents without ensuring they wanted to leave their children behind in the U.S. after being forcibly separated from them, according to a government watchdog report made public on Monday.

U.S. Immigration and Customs Enforcement (ICE) even deported some parents who told deportation officers they wanted their children to come with them, the investigation by the Department of Homeland Security (DHS) Office of Inspector General found.

In May 2018, for example, a migrant father asked to be deported with his daughter, who had been separated from him, the DHS investigators found. ICE deported him the following month without his daughter.

DHS inspectors wrote that ICE records indicated that some parents who said they wanted to be deported with their children were nevertheless expelled from the country without them. 

“Therefore, at least some of ICE’s removals of parents without their children were intentional, and not just inadvertent incidents resulting from human error or inaccurate records,” the 28-page report said.

Even when ICE recorded a parent’s decision to allow their children to remain in the U.S., some of the documents were “significantly flawed,” the report said, noting that the finding suggested “that not all parents who purportedly waived reunification did so knowingly and voluntarily.”

The findings released Monday contradict statements made by high-ranking Trump administration officials, including former DHS Secretary Kirstjen Nielsen, who indicated that migrant parents who were deported without their children opted to leave them behind in the U.S.

“There was no parent who has been deported to my knowledge without multiple opportunities to take their children with them,” Nielsen testified before a House committee in March 2019. 

Despite these statements, DHS investigators found that ICE did not have “clear guidance” on documenting or processing decisions by parents on whether they wanted their separated children to remain on U.S. soil without them.

“The report is consistent with the horrifying facts we discovered in the litigation: that parents were deported without the opportunity to bring their children with them,” Lee Gelernt, the American Civil Liberties Union (ACLU) lawyer representing separated families in federal court, told CBS News. “Throughout the litigation we learned that some parents were even told their child would join them on the plane only to have the plane take off without the child.”

About 2,800 migrant families were separated in the spring of 2018 when the Trump administration implemented its “zero tolerance” crackdown across the entire U.S.-Mexico border. Parents were generally prosecuted for crossing the border illegally, while their children were incorrectly designated as unaccompanied minors and sent to government-overseen shelters.

That border-wide policy, which officials said was designed to deter unauthorized migration, ended in June 2018 after a massive public uproar forced former President Donald Trump to discontinue the mass separations. A federal judge also blocked the practice and ordered the administration to reunite the families it had separated.

More than 1,500 migrant families were split up in late 2017 and early 2018 before “zero tolerance” became a formal policy along the entire border. Many parents were deported without their children during that time. As of May 19, advocates had yet to locate the parents of 391 children, according to a federal court filing.

U.S. District Judge Dana Sabraw, who has overseen the family separations case, also ordered the Trump administration in the summer of 2018 to give separated parents a notice that allowed them to choose between three options: being deported with their children, allowing their children to stay in the U.S. or asking for more time to speak to a lawyer before make a decision.

Prior to the issuance of that notice in July 2018, the DHS investigators found that parents did not “consistently” have the opportunity to reunite with their children before being deported.

One assistant ICE field office director told investigators that during the early implementation of “zero tolerance,” his agents deported parents without asking them whether they wanted their children to join them. Some officers at one field office did try to document the parent’s oral decision, the report said.

The DHS inspector general’s office said it could not substantiate concerns that parents who purportedly allowed their children to remain in the U.S. were misled or coerced into making that decision.

In September 2019, Sabraw, the federal judge, found that nearly a dozen parents were eligible to come back to the U.S. because they had been likely coerced into signing off on their deportation or provided misleading information. Nine of those parents returned to the U.S. in January 2020 to reunite with their children.

President Biden, who has denounced the Trump-era separations as cruel, created a task force soon after taking office to locate migrant parents and children who remain separated and facilitate their reunifications.

Unlike the Trump administration, the Biden administration is allowing eligible separated families to reunite on American soil. Earlier this month, four migrant parents were allowed to enter the U.S. legally to reunite with their children, some of whom they had not seen in over three years.

The ACLU estimates that 1,000 migrant families remain separated.

On Monday, DHS spokeswoman Sarah Peck said the department agreed with the report’s recommendations, which included making sure that ICE deportation agents properly document whether a parent wants to allow their children to remain in the U.S. without them.

“This report’s findings are a tragic reminder of how parents and children were cruelly separated by the prior administration,” Peck said in a statement to CBS News. “We are working tirelessly to reunite separated families and rebuild our immigration system so our laws are administered fairly and humanely.”