PROVIDENCE, R.I. (AP) — The ringleader of a kickback scheme that cost the U.S. Navy $18 million has surrendered to begin a 10-year sentence in federal prison.

The U.S. Marshal's office in Rhode Island says Ralph M. Mariano surrendered on Tuesday to the federal prison facility at Devens, Mass.

Mariano worked for the Naval Undersea Warfare Center in Newport and was most recently assigned to the Naval Sea Systems Command headquarters in Washington, living in South Arlington, Va.

He pleaded guilty to leading a 15-year scheme that used a Georgia-based Navy contractor to funnel kickbacks to himself and others.

Five others have pleaded guilty in the case.

Despite his guilty plea, Mariano has indicated he plans to appeal his conviction and sentence. It's not yet clear on what basis he will appeal.