LAFAYETTE, La. (KPEL) -- Yet another indictment has been handed down in the ongoing investigation into bribery at the Lafayette District Attorney's Office.

U.S. Attorney Stephanie Finley says 64-year-old private investigator Robert Williamson has been indicted on one count of conspiracy, six counts of bribery, one count of Social Security fraud, and one count of making false statements to federal agents.

Williamson has been at the center of a pay-for-privilege bribery scheme in which he would garner favorable treatment for his clients from District Attorney office staff. Finley alleges that from March 2008 until February 2012, Williamson solicited thousand of dollars from his clients to have their cases dismissed. Their cases, usually OWI-related, would be placed into "immediate 894 sessions" by the office staff in exchange for cash and other valuable items, Finley says.

Louisiana law, Article 894 of the Code of Criminal Procedure, provides a procedure by which "a person can plead guilty to a crime with the understanding that the conviction will be set aside if the person successfully completes certain requirements imposed during a probationary period, including community service," Finley says.

During this time period, Williamson allegedly bribed Barna Haynes, the former secretary to District Attorney Mike Harson; former assistant district attorney Greg Williams whose duties included prosecuting OWI cases; Williams' secretary Denease Curry; Acadiana Outreach case manager Elaine Crump; and Acadiana Outreach case manager Sandra Degeyter, according to the federal indictment.

Williamson would also allegedly obtain false community service and driving certificates for his clients, bribing staff at organizations associated with the OWI program, even though his clients did not perform the required service.

Williamson faces up to five years in prison and a $250,000 fine for the conspiracy count, up to ten years in prison and a $250,000 fine for each count of bribery, five years in prison and a $250,000 fine for the count of Social Security fraud, and five years in prison and a $250,000 fine for the count of lying to federal agents.