COLUMBIA, S.C. -- A 44-year-old Greenville man was convicted in federal court on Thursday for conspiracy to murder an FBI agent.

In the fall of 2007, Dwight Spears and two Spartanburg residents, Kenneth Manigan and Marielena Ledy Martinez, agreed to kill a local FBI agent for his role in the investigation into Manigan's drug distribution activities.

Manigan was arrested last October and housed in the Spartanburg County Detention Center to await trial on federal drug charges. According to testimony at trial, he and fellow inmate Spears devised a plan to kill the agent to prevent him from testifying against Manigan.

The men agreed that Manigan would arrange for his friend, Martinez, to post Spears’ bond, give Spears a weapon and help him identify and locate the agent.

Martinez posted Spears' bond, but Spears was arrested 10 days later before he could carry out the plan.

Manigan and Martinez pleaded guilty prior to trial, and Manigan testified against Spears. Both are awaiting sentencing.

Officials said the maximum penalty Spears can receive is a fine of $250,000 and imprisonment for 20 years.