A Navy subcontractor pleaded guilty Friday in Rhode Island for his part in what federal prosecutors say was a kickback scheme that cost the Navy millions of dollars.

Russell Spencer's plea was part of an agreement with prosecutors in which he promised to cooperate with authorities as he has been since investigators approached him in June 2010.

Spencer, 56, pleaded guilty to conspiring to commit bribery in helping funnel money, through his businesses, from a Navy contractor to a civilian Navy employee who prosecutors say then bumped up funding to the contractor. Prosecutors say the scheme cost the Navy between $7 million and $20 million.

The case prompted an internal Navy investigation that resulted in military officials in Washington suspending the contracting authority of Newport's Naval Undersea Warfare Center. The Navy said a host of contracting problems at the facility enabled the scheme.

According to the government, Ralph M. Mariano of Arlington, Va., who worked at the warfare center, initiated the scheme by threatening to use his position to reduce funding for contracts held by Advanced Solutions for Tomorrow if company owner Anjan Dutta-Gupta didn't kick back money to Mariano.

Dutta-Gupta, of Roswell, Ga., has pleaded guilty to paying $8 million in bribes over more than a decade. Mariano has been charged, but not indicted. He has declined to comment on the allegations, and remains free on bond.