FREEPORT, N.Y. (CBSNewYork/AP) — Up to 600 pieces of mail have been stolen from two U.S. Postal boxes on Long Island, according to authorities.

The mail was apparently taken from two green locked boxes used by carriers to pick up mail to distribute on their routes.

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It happened in Freeport on April 7. Some 600 pieces of mail, including first class mail, were taken.

“It’s a lot. It’s a lot, 600 pieces,” Donna Harris, Postal Inspection Service, said.

One box is located at the intersection of West Merrick Road and South Long Beach Avenue; the other one is at Whaley Street and Miller Avenue.

“The carrier went back to pick up mail and it wasn’t there,” Harris said.

Residents along the affected routes have been notified, although as CBS 2’s John Slattery reported, some were already aware that something was wrong.

“I’m missing a couple of bills, credit card bills,” Merlin Singh said.

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One Freeport resident told CBS 2’s Slattery that his neighbor was missing an IRS refund check

Inspectors still aren’t sure whether the boxes were broken into, opened with a key, or left unlocked.

Anyone who sees any suspicious charges on their credit or bank statement should call the Postal Inspection Service immediately, spokesperson Donna Harris said.

Stealing mail is a serious offense that carries a penalty of up 20 years in prison and a $250,000 fine.

This is the second recent incident involving mail disappearing in Nassau County.

Last month, a mail carrier in Seaford was accused of throwing hundreds of pieces of mail into dumpsters.

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