Zack Shelby is a young, handsome, clear-eyed deputy of the White Pine Bay Police Department but is the main villian of the first half of season 1. He's almost immediately attracted to Norma Bates and finds himself drawn into her life and wanting to take care of her. He was often partnered with Alex Romero.
After Norma and Norman dumped Summers' body into the bay, Shelby and Romero found Summers' hand in the lake. There were carpet fibers caught in the watchband, and Norma and Norman were changing the carpets in the motel when Shelby and Romero had visited. The next day, Shelby and Romero returned to the motel with a search warrant. Shelby found Summers' belt underneath Norman's bed and hid it from Romero to protect Norma.Dylan at gunpoint in their house, where he yelled at and physically abused Norma for "betraying" him. In an attempt to protect his mother, Norman attacked Shelby, which caused him to drop the gun he had earlier confinscated from Dylan. Dylan grabbed the gun, Norma ran outside with Norman, and Dylan engaged in a gunfight with Shelby. Dylan eventually prevailed and killed Shelby. (The Truth)