2x23 - The Sentinel

A construction foreman is murdered at a racetrack under renovation, and his body is hidden in a pillar. Weeks later, Banks attends the opening of the racetrack with friends, and Ellison attends a police benefit at the track's turf club. During the benefit event, one of Banks' friends is pushed from the roof, and falls to his death in what looks to the partygoers to be a suicide.