U.S. Postal Service inspectors are investigating the theft of mail from two relay boxes in Freeport earlier this month.
Mail was removed from the large green locked boxes used by carriers to pick up mail to distribute on their routes. On April 7, mail was removed from relay boxes at West Merrick and South Long Beach roads, and at Whaley Street and Miller Avenue, postal officials said.
As many as 600 pieces of mail had been taken, officials said Tuesday.
Such thefts are "highly unusual," said Christine Dugas, a Postal Service spokeswoman in Providence, R.I.
Peter R. Ruh, a postal inspector from Garden City, on Thursday sent a letter to every mail address along the affected routes notifying them of the theft.
"If you had a check or credit card stolen, or you have any information that would be helpful to our investigation, please call (516) 228-7672," the letter said.
Rita Tancredi, a 45-year resident on West Merrick Road, said she thought something was wrong when she didn't receive any mail on April 7.
"I don't think I had anything important in the mail," Tancredi said. "The next day was back to normal."
Donna Harris, a spokeswoman for the Postal Inspection Service in Manhattan, encouraged residents on those routes to call the local number or 877-876-2455 to report missing mail.
"If they saw anything suspicious, they should call us," she said. "Our number one goal is to make sure that mail gets to where it is being sent."
The Inspection Service would not detail the investigation or what important mail has been reported as missing by residents.