The U.S. Postal Service (USPS) has been receiving backlash for months after reports of mail theft and delivery slowdown brought by new changes.

Aside from that, USPS has also been facing an undisclosed problem, which is its lack of reliable system for tracking mail theft.

USPS law enforcement arm acknowledged the shortcoming after reports prompted by anecdotal accounts of rise in mail theft around the country.

The anecdotal accounts were sought and received mail theft figures done through a Freedom of Information Act request.

The Postal Inspection Service data found that mail theft reports increased by 600 percent over the past three years. This from 2017's 25,000 to roughly 177,000 through Aug. 24 of this year.

The Postal Inspection Service said the figures actually reflect multiple types of customer complaints, not just involving theft.

However, the agency said it could not provide figures on mail theft as there are limitations in the internal system it uses to get customer reports.

"We discovered that the mail theft complaint numbers provided to you were overstated due to the fact they included a significant number of reported customer complaints unrelated to mail theft, such as mailbox vandalism, mail delivery issues, and matters unrelated to the mail or Postal Service," the agency said in a report.

The agency added that the reporting system allows for an individual to label their complaint as mail theft.

However, USPS also said that the system is not designed to automatically see which of these are real complaints of mail of U.S. mail. The Postal Inspection Service said it is planning to develop a system to better track mail theft complaints.

"For fiscal year 2021, we are developing a plan to more effectively capture our internal review of these complaints in order to track and report mail theft complaint data," the agency noted in a report.

The disclosure of USPS's complaint data and revelation of mail theft not being properly track comes during a close scrutiny of the agency's ability to handle the influx of mail-in ballots.

Janet Lauritsen, a criminologist, said that it is startling for her. Lauritsen said the agency is supposed to investigate these issues.

"So how can it be possible that they do not have the data necessary to do those investigations? I can't make sense of it," Lauritsen said in a report.

She added that despite the Postal Inspection Service explanation, the huge increase in complaint numbers is troubling.

Lauritsen added that the trend in the data still shows something, adding that it seems their statements are "designed to minimize alarms over the state of Postal Service."

USPS did not respond to requests for comment.

Postal Service Office of Inspector General spokesperson referred questions to the Postal Inspection Service.

Reports said that without accurate figures, it will be hard to say if the country is facing an epidemic of mail theft. Police officials noted that several areas in the country are seeing increase in the crime.

One postal police officer, who requested anonymity, said mail theft has gone through the roof.

"It's not even a question. Mail theft has gone through the roof... And that's only what's reported. If they steal mail that you don't know was coming, you don't report it," the officer noted.

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