Timothy Oliver, the Plymouth lawyer charged with fraud in a purported Libyan land deal, may be facing additional unspecified charges in the case, according to new court documents.

Oliver last month pleaded not guilty to federal charges that he bilked a Mexican construction company out of $500,000 with the promise of work on a land development project in Libya.

Since then, his defense attorney, Daniel Scott, has filed a series of documents seeking at first to withdraw from the case, then to stay involved in it.

"This is a complex white-collar case," Scott wrote in a motion to get out of the case. "There will probably be several superseding indictments adding new and different charges."

In that motion, Scott said Oliver could not meet the "terms and conditions" of a retainer agreement to hire him and his law firm, Kelley Wolter & Scott.

In a subsequent filing, Scott said, "This appears to be a classic federal white-collar fraud prosecution … requiring attorney and investigative commitment easily exceeding 1,000 hours."

That level of representation could mean out-of-pocket expenses to Scott's law firm easily exceeding several hundred thousand dollars.

Earlier this week, however, Scott dropped the request to withdraw, a move that suggests Oliver did meet his retainer requirements.

Scott did not return a call seeking comment. Neither did the U.S. attorney's office that is prosecuting Oliver.

There was no indication in the May 12 indictment of Oliver that additional charges were pending. Oliver was indicted on six counts of wire fraud on charges that he took $500,000 from the Mexican firm ARS Tectonica to secure a line of credit but instead spent nearly all of the money for himself.

However, Oliver does have a checkered history of land deals elsewhere in Minnesota and in Mexico.

He was admonished by the Minnesota Commerce Department in 2006 in a Mexican real estate development project for not registering with the state lots it was selling to Minnesota investors.

In 2011, Oliver and a partner were criticized by a federal judge for making "fraudulent misrepresentations" in a northern Minnesota land deal. U.S. District Judge Donovan Frank awarded $2.4 million to Meecorp Capital Markets in that case.

Separately, the state Commerce Department revoked Oliver's insurance license in May because of "several" adverse lawsuit findings against him.

Oliver, 60, is a lawyer with the small Twin Cities firm of Oliver & Johnson.