A former police major who retired from the Honolulu Police Department amid allegations that he extorted money from the operator of an illegal gambling house and tried to cover it up pleaded guilty in U.S. District Court this morning to charges unrelated to the alleged extortion.

Carlton Nishimura, 57, was facing federal extortion conspiracy, witness tampering, lying to investigators, methamphetamine possession and tax evasion charges.

Nishimura pleaded guilty this morning to lying to investigators and to filing a false 2005 tax return by under-reporting his income by about $9,000.

In exchange for his guilty pleas, the federal prosecutor is expected to have the other charges dropped at sentencing in October.

The government said he took money from a gambling house operator to protect the operation and to harass the operator’s competitors. The government also said Nishimura lied to investigators about what he told a witness, told the witness to lie, failed to report the extortion money as income and possessed 16 grams of methamphetamine in his Waianae home.

The charges that are being dropped are related to the government’s key witness in the case, Doni Crisolo, who is also known as Doni Mei Imose. 

Crisolo pleaded guilty in July 2009 to conspiracy for her role in a methamphetamine trafficking ring but has yet to face sentencing.

She testified in front of the federal grand jury that indicted Nishimura in February 2011 on charges of extortion conspiracy, witness tampering and lying to investigators. 

The following month, Crisolo secretly recorded herself telling her then-lawyer that she lied to the grand jury under pressure from the FBI, that she felt bad about what she did and that she intended to set things straight to save her friendship with Nishimura.