WASHINGTON (AP) -- An Interior Department lawyer who says he was ordered to dispose of some Indian trust records will be questioned next week in connection with a lawsuit over the government's handling of accounts worth $500 million.

In an affidavit made public Thursday, Ralph Williams said he was given the job of reconciling discrepancies in some of the accounts in late 1997. Once his work was done, he was supposed "to ensure that . . . any other information which was inconsistent from my findings could be purged from the files," he said.Williams said he declined to get rid of the material because he thought it would be illegal. He said the instructions came from the department's deputy solicitor, Ed Cohen.

Interior officials denied any wrongdoing.

Last month, U.S. District Judge Royce Lamberth held Interior Secretary Bruce Babbitt and Treasury Secretary Robert Rubin in contempt for the government's two-year delay in turning over checks and other documents related to five account holders who filed the lawsuit. It was not clear whether Williams handled any of those documents.

Lamberth released the affidavit Thursday along with an order protecting Williams from retaliation by the department.

Williams is scheduled to be questioned by lawyers in the case on Tuesday.

The department's chief attorney, Solicitor John Leshy, issued a brief statement defending Cohen and denying that his office would attempt to dispose of records that are relevant to the lawsuit. Department officials declined to make Cohen available for an interview.

Lawyers for the Indian plaintiffs brought Williams' allegation to the judge's attention after they were approached recently by Williams' attorney.

Williams still works in the solicitor's office. He did not respond to a request for an interview Thursday.

Interior manages $2.5 billion belonging to tribes in addition to the $500 million owned by individual Indians. The money includes lease revenue, royalties and court settlements. The funds were mismanaged for decades, and lawyers for the Indians say the government could be liable for billions of dollars in claims.

Legislation was introduced in the Senate Thursday to let tribes have their money transferred to private banks.