William Moniz was a member of the Los Pollos Hermanos security staff, serving as an enforcer for Gustavo Fring's drug empire under direct supervision of Mike Ehrmantraut. One of Fring's offshore accounts was set up in his name.
He was arrested following the murder of Gus and the discovery of the methamphetamine superlab at Lavandería Brillante and his accounts were seized. The organization initially continued to pay him through a series of dead drops via his lawyer Dan Wachsberger. The arrest of Dan and the subsequent disappearance of Mike ended this practice. Fearing that he would testify about his involvement Fring's successor Walter White had him, and nine other members of the organization, murdered in prison.
Moniz was stabbed multiple times by Jack Welker's hitmen and then thrown over a balcony. ("")
- The scene where he was thrown off the balcony was filmed with several tall cardboard boxes onto which the actor fell. A behind the scenes video says that cardboard can be as protective as cushioning