WASHINGTON (CNN) -- A lawyer who worked with high-powered Washington lobbyist Jack Abramoff, is expected to testify against him as part of a plea bargain with the Justice Department, two government sources have told CNN.Michael Scanlon will plead guilty Monday after being charged with one count of conspiracy on Friday as part of an ongoing federal criminal investigation of the two men's lobbying activities, the sources said.The developments came after the prosecutors filed a "criminal information" in U.S. District Court, alleging that Scanlon conspired to "corruptly offer and provide things of value, including money, meals, trips and entertainment, to federal public officials in return for agreements to perform official acts" benefiting Scanlon and his lobbyist partner.The partner is identified in the court documents only as Lobbyist A and is not facing charges. One government official told CNN that lobbyist is Abramoff.Prosecutors also allege Scanlon was trying to "devise a scheme and artifice to defraud" lobbying clients.Justice Department officials would not comment on any possible plea deal and would say only that a Monday hearing on the case is planned.Prosecutors also detail a "stream of things of value" given to an unnamed congressman, identified in the court documents as Representative No. 1, including a "lavish" trip to Scotland to play golf, tickets to sporting events, and campaign contributions to the representative and his political action committee in exchange for a series of actions by that representative.In the court documents, prosecutors allege Scanlon and Lobbyist A, "together and separately, sought and received Representative No. 1's agreement to perform a series of official acts, including but not limited to agreements to support and pass legislation, ... meetings with Lobbyist A and Scanlon's clients, and advancing the application of a client of Lobbyist A for a license to install wireless telephone infrastructure into the House of Representatives."Officials would not identify Representative 1.Among the high-profile clients of Scanlon and Abramoff were Indian tribes, which hired them to gain political access in Washington."It was a purpose of the conspiracy for Scanlon and Lobbyist A to enrich themselves by obtaining substantial funds from their clients through fraud and concealment and through obtaining benefits for their clients through corrupt means," the complaint states.The government alleges the conspiracy lasted from January 2000 through at least April 2004.A phone call to Scanlon's lawyer seeking comment was not immediately returned.Prosecutors allege Scanlon and the lobbyist "would falsely represent to their clients that certain of the funds were being used for specific purposes, when in fact, Scanlon and Lobbyist A would use those funds for their own personal benefit and not for the benefit of their clients."CNN Correspondent Kelli Arena and Producer Ted Barrett contributed to this report.