Defense attorneys in the corruption trial of former House Speaker Michael Madigan on Wednesday attacked the credibility of a key prosecution witness, questioning his motives for cooperating with the FBI and grilling him over attempts to hide money in a divorce and his recent attempted purchase of a gun to shoot rattlesnakes.

Seizing on a tactic strengthened by a recent U.S. Supreme Court decision, defense attorneys in the Michael Madigan corruption trial began their cross-examination of a key witness Tuesday by trying to distinguish between exchanging jobs for official actions and simply currying favor with the formidable ex-House speaker.

The corruption charges against former House Speaker Michael Madigan are in many ways tethered to his longtime confidant, Michael McClain, a self-described “agent” of the speaker who was captured on FBI wiretaps pushing contract and job requests that he said came directly from Madigan himself.