A former New York police detective accused of moonlighting as a hit man for the mob pleaded guilty Tuesday to one count of filing a bogus income tax return, federal prosecutors said.

Louis Eppolito, currently in federal custody, faces sentencing May 9 in U.S. District Court here. The maximum penalty in the case is three years in prison and a $250,000 fine.

Greg Brower, U.S. attorney for Nevada, said that according to a plea agreement, Eppolito and his wife, Frances, filed a tax return for 2000 that reported income of just over $127,000 when their actual income was more than double that amount.

Brower said Eppolito also failed to declare $175,000 in income from screenplay writing in 2001 and 2002.

Eppolito and another former New York detective, Stephen Caracappa, were accused of participating in at least eight mob-related killings while working for the Luchese crime family. The two detectives retired in the early 1990s and moved to Las Vegas, where they were arrested in March 2005.

In 2006, a New York jury found the pair guilty of a racketeering conspiracy responsible for multiple murders and other crimes. Two months later a federal judge dismissed that case after determining that the statute of limitations had expired for the racketeering charges, which allegedly occurred from 1986 and 1990. The judge's decision is under appeal.

The men still face drug and money laundering charges.

Eppolito's 1992 autobiography, "Mafia Cop: The Story of an Honest Cop Whose Family Was the Mob," details his police career and his Mafia connections.