The Diocese of Paterson, New Jersey, is missing a large batch of donations with parishioners urged to monitor bank accounts amid an investigation into the whereabouts of the funds.

A letter to diocesan residents from Bishop Kevin Sweeney, obtained by CNA, said the missing funds were part of the Paterson Diocese's ministries appeal.

The diocese for 10 years has used a third-party firm that "specializes in processing and recording donations," Sweeney said.

That arrangement is "used by many dioceses and nonprofits to ensure there is an independent, 'arms-length' distance between the office that conducts a fundraising effort and the funds that come in," the bishop noted.

Sweeney said workers on Oct. 30 and Oct. 31 dropped appeal responses from "approximately 1,700 parishioners" into a FedEx drop box. The appeals were addressed to the processing firm.

"Unfortunately, the packages never arrived at their destination, and the tracking number for each package used to monitor the location was never entered, making it impossible to know their current whereabouts," the bishop said.

Of the 1,700 responses, Sweeney said, the diocese estimates "approximately 500 ... may have contained cash, checks, and credit card information."

The prelate said the diocese has been in "constant contact with FedEx about this issue" and that officials were "not ruling out foul play." Law enforcement has been notified, he said.

Sweeney said the diocese has changed its processing procedures. "[We] now bring all packages to a FedEx store where we watch it get scanned and receive a receipt and tracking information," he said.

The bishop urged parishioners to "monitor your credit card activity or checking account to make sure there are no irregularities."

Sweeney acknowledged that it was "distressing that an action beyond our control may have impacted even a small number of our faithful supporters."

"What makes this even more upsetting is a concern that this could impact those who want to give to the Diocesan Ministries Appeal but may now be hesitant," he noted. "This has the unintended effect of impacting funding to the important and vital ministries in our diocese, such as Catholic Charities, where the need is so great."

"We hope that this does not deter the faithful from supporting our appeal, especially now that a solution is in place to ensure the tracking of every package," Sweeney added.

On its website, the diocesan appeal says the funds raised go toward Catholic education, seminarian support, senior priest retirement, and taking care of people with special needs.