Proof of Lies (2006)

Chicago real estate lawyer Chuck Hartley's career is in a slump, so it feels bitter when his wife, genetic researcher Christine Hartley, asks him to set up a trust for the proceeds of her institute's successful project on predisposition to addiction. At Chuck's college reunion, she meets and starts an affair with Sam Buckner, a playful crime mystery author. That detonates a series of deceptions and crimes.