PENSACOLA, Fla. (AP) _ A rural mail carrier has been indicted after officials found 10 first-class letters addressed to others buried in about five tons of mail on his property.

If convicted, William E. Ryan, believed to be in his 50s, faces up to 50 years in prison and fines of up to $2.5 million.

A federal grand jury Thursday indicted Ryan of nearby Milton on 10 counts of obstructing the delivery of mail, one count each for five tax notices from a county property appraiser's office and five letters from the county supervisor of elections' office.

''We don't know what his motive was,'' said Assistant U.S. Attorney Stephen P. Preisser.

The 10 first-class letters were believed to contain notices to taxpayers of proposed changes in their property taxes or voter registration cards.

The hoard of third-class business bulk mail included sweepstakes offers, free-samples and catalogs dating back three years, postal authorities said. They discovered the mail at and near Ryan's home after receiving a tip.

A front-end loader was used to load the mail, much of it rain-soaked and mildewed after laying in the woods, onto trucks.

No immediate attempt was made to arrest Ryan, who has been cooperating with investigators, Postal Inspector Richard Jordan of Mobile, Ala., said Friday.

Ryan has been a carrier for 15 years, the last three in Pensacola. After the missing mail was found, he was suspended without pay and notified that he would be fired, Pensacola Postmaster Ben Jasek said.