Your Reporter Karen Morfitt specializes in coverage of Colorado's Jefferson County. Share you story ideas with her by sending an email to yourreporter@cbs.com.

Despite efforts to deter them, thieves in Colorado are continuing to steal credit cards, checks, ballots and even prescription medication from mailboxes.

CBS Colorado has reported on the issue of mail theft several times over the past several years. More than a year ago, top officials within the U.S. Postal Inspection Service told CBS Colorado steps were being taken to address it, specifically upgrading locks across the Denver metro area.

"This is a problem right now, but it won't be a forever problem," Melissa Atkin told CBS Colorado investigative reporter Karen Morfitt in the fall of 2024.

The issue has persisted for some time after those assurances.

Investigators know where the thefts are happening and how they are happening, and they have the ability to stop it by changing locks. But USPS has said changing locks will be a long, expensive process.

"I don't think we realized the magnitude of it initially," said Karen Hagans.

Hagans has lived in Denver's Lowry neighborhood for about 20 years. Recently, she said her mail began disappearing nearly every day.

"All of the boxes where they put packages were open. There was stuff thrown on the ground on the street, and you realized that if you didn't go get your mail the minute it was delivered, you couldn't trust that it was there," Hagans said.

Frustrated by the pressure to beat thieves to her mail, Hagans rented a post office box, one of the only solutions offered by the USPS. But she said she then had trouble forwarding her mail and was mistakenly identified as having moved away.

"They called me and said, 'We see that you moved. Do you want service at your new location?' I said, 'What do you mean I moved?' Hagans said.

Her experience is not unique, nor is the Lowry neighborhood.

Federal court records show thieves with master keys have been targeting cluster mailboxes for years.

"It's the same master key used throughout the Intermountain West," said Mary Carr, executive director of the Lowry Community Master Association. "Some of Lowry's mail was recovered in Wyoming and vice versa because the folks robbing the kiosks are moving up and down the I-25 corridor."

Carr said the association is legally responsible for securing the mailboxes, but it has no control over the locks, which are USPS property.

"There's no pattern to when they hit the boxes -- at night, in the middle of the day -- there's no pattern to it," Carr said. "We are at a loss."

After making repeated phone calls, sending emails and visiting in person to local postal offices, Carr says their efforts to work with the U.S. Postal Inspection Service went nowhere. They then turned to lawmakers for help.

"There really isn't anywhere to go except the Postal Inspection Service," Carr said. "They committed to Congresswoman (Diana) DeGette's office that they would be replacing the master key system with a scannable key."

However, Carr said they have not received a timeline for those upgrades but were told areas with the highest number of thefts will be prioritized.

They have since outfitted every kiosk with a QR code, allowing residents to make immediate theft reports.

"The squeaky wheel gets the grease, so the more reports we have of mail theft, the more attention it will get," Carr said.

While Lowry waits for locks to be upgraded, investigators say another crime happened: A mail carrier was robbed and a "piece of USPS property" was stolen. The USPS is offering a reward of up to $150,000 for information.

"I don't think that's really going to address the problem," Hagans said. "If these keys are out there, maybe it's one person or maybe it's many. They need to think about the integrity of the system."

In response to questions from CBS Colorado, a USPS spokesperson sent the following statement:

"The Postal Service has been implementing a series of nationwide security enhancements, including the deployment of high-security collection boxes and upgraded cluster box units. These upgrades are part of a broader, multiyear initiative to reduce opportunities for mail theft and limit criminals' ability to misuse stolen arrow keys.

To protect the integrity of these security measures, USPS does not disclose specific locations, quantities, timelines or operational criteria related to where or when upgrades occur. This includes information about how many boxes have been upgraded, how locations are selected or any thresholds related to theft activity. These safeguards are in place to prevent criminals from identifying vulnerabilities or targeting specific neighborhoods.

USPS continues to explore and pilot enhanced access control technologies, including electronic key systems. These efforts are ongoing, and details about deployment locations or timelines are not publicly released for security reasons.

USPS maintains strict internal controls for the issuance, tracking and use of arrow keys. While we cannot discuss specific numbers of keys or internal accountability procedures, we can assure you that USPS has reinforced policies and training to support proper key handling and reduce opportunities for misuse or theft. Any incident involving a stolen or misplaced key is immediately reported to USPIS for investigation, as applicable by USPIS and/or the U.S. Postal Service Office of Inspector General."

Mail theft in Colorado continues years after USPS vowed to make changes