Former Knight Oil Tools executive Mark Knight entered a written plea of not guilty Tuesday on racketeering charges.

Knight, 57, of Lafayette, was indicted in July on two counts of racketeering in connection with a scheme to frame his brother, Bryan Knight, for criminal drug activity.

Mark Knight was president and CEO of the business until January. He still served as board chairman until the spring. He was arrested in April.

Meanwhile, Bryan Knight, 56, of Lafayette, was charged Aug. 28 via a bill of information with one felony count of simple criminal damage to property, according to documents with the Lafayette Parish Clerk of Court Office.

Assistant District Attorney Ronald Dauterive wrote in the bill of information that Bryan Knight on June 14 intentionally damaged a mailbox valued at more than $500 belonging to Mark Knight.

Mark Knight is accused of involvement with three other men in a June 2014 scheme in which two magnetic boxes of illegal drugs were attached to Bryan Knight’s vehicle. A tip was phoned into police that Bryan Knight was carrying illegal drugs. He was stopped and arrested, but the charges were dropped in December.

Investigators believe Mark Knight paid Russell Manuel, 48, of Lafayette, an employee at Knight Oil Tools, and two police officers $100,000 plus gifts to assist with the scheme to frame Bryan Knight.

Jason Kinch, 39, of Lafayette, was a deputy with the Lafayette Parish Sheriff’s Office since 2005 and served with Metro Narcotics since 2013. Corey Jackson, 50, of Youngsville, was with the Louisiana State Police since 2004. They, along with Manuel, also were charged with two counts of racketeering.