KEARNEY, Neb. (AP) — A former Nebraska probation officer sentenced to federal prison for having sex with probationers, then lying about it, is appealing his conviction.

An attorney for 57-year-old Thomas Peterson, of Kearney, filed notice of intent to appeal back in November.

Peterson began serving his nine-year sentenced on Monday.

Peterson was convicted by a jury in July of four counts of violating probationers’ civil rights and one count of lying to the FBI.

Prosecutors say he had sex with four different women while they were on probation under his supervision and that he tipped off probationers to planned drug tests. Officials say he also threatened to have one woman’s probation revoked unless she left the state.