Homeland Security Dept. gathered millions of money transfer records, senator says.

The Department of Homeland Security collected records on millions of money transfers between people in Mexico and four American states in what Senator Ron Wyden said amounted to a secret “bulk surveillance” program.

The program began in 2019 and was halted in January, according to a letter that Mr. Wyden sent on Tuesday to the agency’s inspector general. Mr. Wyden, an Oregon Democrat and chairman of the Senate Finance Committee, asked the inspector general to open an investigation into the program’s operations and whether any laws were broken.

The department gathered six million records on transfers of $500 or more that were sent to or from Arizona, California, New Mexico, Texas and Mexico, according to the letter. Homeland Security officials acquired the records by sending subpoenas to Western Union and Maxitransfers, Mr. Wyden said.

The data was also provided to the Transaction Record Analysis Center, an entity that allows federal, state and local law enforcement agencies to share financial records.

The TRAC database “has enabled hundreds of law enforcement agencies to have unfettered access, without any supervision by the courts, to the financial transactions of millions of people,” Mr. Wyden wrote.

Meira Bernstein, a spokeswoman for the Department of Homeland Security, said the agency had stopped collecting the data while it reviewed the program. The department “is committed to ensuring that our criminal investigative methods are not only effective in combating transnational criminal actors and other security threats, but also consistent with the law and best practices,” she said.

A Western Union spokeswoman, Claire Treacy, said the company was “committed to protecting the personal data of our customers, as well as combating serious criminal activity such as money laundering, human trafficking and human smuggling.”

Officials from Maxitransfers and TRAC and id not immediately respond to requests for comment.

Mr. Wyden cast the Homeland Security program as a replacement of a long-running tracking effort by the Arizona attorney general’s office. A 2010 settlement with Western Union over money-laundering allegations required the company to share extensive data on its customers’ money transfers with Arizona and TRAC. That agreement expired in 2019 — which was when, Mr. Wyden said, Homeland Security stepped in and began issuing its own demands. The department expanded its demands to include Maxitransfers in 2021.

Ms. Treacy said TRAC was an agency of the Arizona attorney general’s office at the time of the court order.

Mark Brnovich, a Republican, became Arizona’s attorney general in 2015. Katie Conner, his spokeswoman, said the office had used TRAC’s data “to combat human and drug trafficking.”

She added, “It is ironic that during a historic border crisis, this would be the focus of any U.S. senator.”