A postal carrier in Northern California was threatened at gunpoint while delivering mail and robbed of mailbox keys on Oct. 23, becoming the latest victim of a growing national crime trend, according to police and postal officials.

“At this point, this is a nationwide problem where letter carriers are being robbed for postal keys,” U.S. Postal Inspector Matthew Norfleet told The Epoch Times on Oct. 24.

Criminals use the keys, which open multiple mailboxes at apartment complexes or other community locations, to steal checks and credit cards.

The latest incident occurred at about 2:15 p.m. in Roseville, California, according to local police, while the mail carrier was walking the usual route.

“The suspect demanded the victim’s postal keys, after a brief struggle, the suspect displayed a handgun, and stole the victim’s keys,” Roseville police posted on social media Wednesday.

All residents in the 95747 ZIP code were warned by police to “be vigilant and take immediate measures to prevent mail theft and mail fraud.”

The 95747 area of Roseville, about 25 miles northeast of Sacramento, is home to nearly 76,000 residents, according to the U.S. Census.

Residents were advised to check their mail daily, keep an eye out for missing important documents or checks, and place a hold on their mail if they go on vacation.

Earlier this month, burglars broke into two U.S. Postal Service locations in Isleton and Ryde, both also in Northern California, and stole mail-in ballots, laptop computers, and other mail, according to the Sacramento County Sheriff’s Department.

No suspects have been identified in the Oct. 23 robbery, according to Norfleet.

“If anyone in the area on Mockingbird Street [in Roseville] has video of the robber, that would be helpful,” he said.

The U.S. Postal Service is offering up to $150,000 for any information that leads to an arrest and conviction of the robber, or any other suspect who has threatened a postal worker.

The postal inspection service, the law enforcement arm of the Postal Service, has seen an uptick in the theft of mailbox keys in California and nationwide, Norfleet said.

“We know there is an underground market for these mail keys,” Norfleet said.

Authorities say thieves pried open the front door of the U.S. Post Office in Ryde, Calif., a  community in Sacramento County, on Oct. 9. (Sacramento County Sheriff's Department)

The theft of mailbox keys has existed for years, but has grown rapidly since the COVID-19 pandemic in 2020, he added.

“Since the pandemic, robberies of carriers have become widespread across Northern California and across the country,” Norfleet said, “It’s something postal carriers are worried about everywhere.”

Mail carriers became a preferred target of thieves during the pandemic because many retailers had closed, according to the Pacific Research Institute, an advocate of free markets.

U.S. Postal Service vehicles sit in a parking lot at a mail distribution center on Feb. 18, 2015, in San Francisco. The Postal Service has reported an uptick in mail carrier robberies since the pandemic. (Justin Sullivan/Getty Images)

The postal inspection service encourages the public to report any theft of checks or credit cards, even if the theft is corrected by their banks.

Reporting mail theft to the postal service or police can directly affect the health and safety of postal carriers, according to Norfleet.

“We need the information, because we want to find the people profiting from these robberies,” he said.

Anyone with information or surveillance video of the Roseville robbery, or information about any other mail theft or robbery of a mail carrier, is urged to call the Postal Service’s 24-hour hotline at 877-876-2455.