Charles Banks faces 20 years in prison after pleading guilty to defrauding Tim Duncan

SAN ANTONIO -- An ex-financial adviser to retired Spurs star Tim Duncan has pleaded guilty in a multimillion-dollar fraud case and faces up to 20 years in prison.

Federal prosecutors said Charles Banks, 49, of Atlanta pleaded guilty Monday in San Antonio to one count of wire fraud.

Investigators say Banks manipulated Duncan -- identified in court documents as "T.D." -- into guaranteeing payment of a $6 million debt related to a merchandising business. Prosecutors say Banks failed to disclose commissions and loans he received in the deal.

Duncan previously sued Banks over what he alleged were more than $25 million in failed investments.

Banks remains free on bond pending sentencing. He could be ordered to make restitution to Duncan, who retired last year after five NBA championships with the Spurs.