A Justice Department proposal to collect DNA samples from around 748,000 immigrants who cross the border annually would create a database that ostensibly would be used to fight crime but is being criticized by rights advocates as a particularly personal invasion of privacy that could be misused to pursue immigrants and their family members.

“It’s the most intimate information that you can take from someone. It is information you can use to find their family members, to know their histories,” Naureen Shah, senior advocacy and policy counsel at the American Civil Liberties Union (ACLU), was cited as saying by NPR. “And we’re going to be taking it from people against their will.”

The U.S. has been mulling the effort, which would apply to immigrants taking into custody, but the Attorney General William Barr filed a proposed rule to “restore the Attorney General’s plenary legal authority to authorize and direct all relevant Federal agencies, including the Department of Homeland Security, to collect DNA samples from individuals who are arrested, facing charges, or convicted, and from non-United States persons who are detained under the authority of the United States.”