Carefully tracking a yearslong U.S. attorney’s probe into corruption at the United Auto Workers, General Motors Co. general counsel Craig Glidden and his outside counsel at Kirkland & Ellis began to see a pattern emerging.

On Wednesday the GM lawyers revealed what they saw in a federal racketeering lawsuit filed against Fiat Chrysler Automobiles NV. The suit accuses Fiat Chrysler of “a systemic and near decade-long conspiracy to bribe senior union officials to corrupt the collective bargaining process and labor relations,” to GM’s detriment.