A worker at the U.S. Postal Service's Apex branch has resigned after investigators found more than 100,000 pieces of undelivered mail at his home, according to federal authorities.

Postal service investigators have turned over some of the evidence to the U.S. Attorney's Office in Raleigh and anticipate federal charges will be filed, said Dan Mihalko, a spokesman for the Postal Service's Office of the Inspector General.

The name of the former postal service employee, who lives in Raleigh, has not been released, and efforts to talk with employees leaving Apex's Post Office Tuesday evening were unsuccessful. U.S. Attorney's Office spokeswoman Robin Zier said she could neither confirm nor deny the existence of any investigation or impending charges.

Mihalko said, however, that investigators are still sifting through the mountain of catalogs, coupons and other discovered mail with the intention of delivering any first-class mail to its intended recipients.

"A big part of the investigation right now is focused on what exactly is there. If there's first-class mail, and it's of value that can be delivered -- in other words it has some time value to it -- we're certainly going to deliver it," Mihalko said.

"Even if it's four or five years old."

Special agents from the inspector general's office searched the employee's home last week after fielding a tip from a meter reader.

The suspicious meter reader made the call after seeing a large pile of mail on the back deck of the employee's home, Mihalko said.

"This type of activity is really a rarity with postal employees," Mihalko said.