Rep. Elise Stefanik’s campaign is accusing postal workers or contractors of opening mail and stealing nearly $20,000 in campaign donations.

In a letter to Postmaster General Louis DeJoy, a lawyer for the New York Republican alleges that packages containing donation checks sent by the campaign were ripped open on four separate occasions between June and November. The packages contained campaign contributions totaling nearly $20,000, the letter states.

“These repeated security failures by USPS have not only resulted in the loss of … campaign contributions, but also — and more alarmingly — have exposed hundreds of Congresswoman Stefanik’s campaign supporters to potential identity theft or financial fraud,” the campaign’s lawyer, Michael E. Toner, wrote with two colleagues from the Wiley Rein firm.

“Evidence indicates that Elise for Congress’s packages were plundered by a USPS employee or contractor while the packages were in transit,” the letter states.

In a Nov. 16 letter to Stefanik’s campaign, the U.S. Postal Inspection Service said it recovered a piece of mail that had been “targeted for theft” at the FedEx International Hub in Memphis. The Postal Service contracts with FedEx and other private companies to transport first-class mail.

“Currently, Elise for Congress is continuing to identify our grassroots donors who have been affected by this and look forward to a speedy response from Mr. DeJoy,” a spokesman for Stefanik said. 

Postal Service spokesman Dave Paretenheimer said the agency received Stefanik’s letter on Thursday and would respond to her attorney “directly with our findings in this investigative matter.”

The campaign says the Postal Service has failed to adequately investigate the allegations.

“Our clients have been disappointed by the U.S.P.S. thus far to these brazen incidents,” the letter states. “The U.S. Postal Inspection Service — which recovered the discarded, ripped open packages in Memphis — has not returned our client’s calls.”

The U.S. Postal Service Office of Inspector General is investigating the theft, Toner said in the letter, but “they indicated it would be difficult to identify the USPS employees or contractors who perpetrated these crimes unless and until one or more of Elise for Congress’s supporters becomes the victim of identity theft or financial fraud.”

Tara Linne, spokeswoman for the Office of Inspector General, said the office received a complaint that a package containing checks and contributions for Stefanik’s campaign arrived with its contents missing. The office immediately launched an investigation, even though officials were told that the Postal Service had returned the previously missing checks, Linne said.

“By October, our investigation had not identified evidence of employee involvement,’’ Linne said in an email. “Additional allegations were raised just this week.”

Linne said the case appears to be within the jurisdiction of the U.S. Postal Inspection Service, which handles complaints of mail theft by nonemployees, and not the Inspector General’s Office, which investigates employee misconduct.

She disputed the Stefanik campaign’s assertion that it did not take the allegations seriously. “We take our mission and responsibility to investigate fraud, waste, and abuse very seriously. We will continue to work with our law enforcement partners to identify and hold responsible those who take advantage of the public’s trust in our postal system,” Linne said.

Toner is asking DeJoy to provide a list of steps the Postal Service is taking to investigate the thefts and what it will do to ensure Stefanik’s campaign won’t become the victim of mail theft in the future.

The letter also asks the Postal Service to outline the ways it intends to prevent, detect and prosecute mail theft nationwide.