He and Officer Green served as the backup team, when Detective Olivia Benson went to talk to Abraham Ophion about Melanie Cramer. The three of them got shot at from Abraham's building, and had to take cover behind a car.
Zermeño later entered Abraham's house, alongside several ESU's, after shots could be heard from the outside. He came out devastated, because he couldn't bear the sight of the bodies of several children.
He would also help in the search for Melanie's mother, Cindy, and later in the search for Abraham and Melanie. He served as backup for Detective Benson, when they found Melanie in an abandoned warehouse. She shot Zermeño in the leg, and threatened to kill him. Benson convinced her to let him go, because he was injured. Zermeño didn't want to leave Benson behind, but Benson ordered him out of the room. (SVU: "Charisma")