Norman St. John, (played by Robert Wisdom), is a Panamanian drug kingpin incarcerated at Sona, where he is the leader of the prison and is at the top of the prison hierarchy. He appears only in season 3 where his role is similar of that of John Abruzzi in season 1. Ruthless and violent, he earned the nickname "Lechero" when he, at the age of 13, disguised himself as a lechero (milkman) in order to kill his mother's rapist. The character serves as an antagonist and enemy to the protagonists in the early episodes of season 3, but later becomes an uneasy ally. Lechero is introduced in the season 3 premiere episode Orientacion. Aware of Michael Scofield’s ventures as a fugitive from the United States, Lechero views him as a threat to his rule and plots to get rid of him by setting Michael up in a fight to the death with another prisoner. However, Michael survives. Lechero also meets T-Bag in this episode and accepts him as his underling. The relationship between him and Michael continues to be characterized by deceit and mistrust in the next few episodes, like in Call Waiting, when Michael steals Lechero’s cell phone. But Lechero learns in Fire/Water, that Michael can be useful as well when he restores water to the prison. Lechero grows increasingly paranoid as the season progresses, and is later tricked by T-Bag that his cronies are planning a coup against him, successfully manipulating Lechero to enlist T-Bag as a spy.
In Good Fences, Lechero gets in trouble when the electrical system in the prison stops functioning. Remembering that Michael is an engineer, he quickly enlists Michael's help to fix the system, in exchange for a new cell in the prison block. He is later approached by Bellick, who warns him that Michael cannot be trusted and that he will trick Lechero as he tricked Bellick. At first Lechero is skeptical but then he decides to see for himself, and when Michael successfully outwits him and repairs the prison's electrical system, his trust in Michael is solidified. He later punishes Bellick for the bad information by scalding him with hot coffee. In Photo Finish Lechero slits Cheo for taking tribute from Augusto (It was actually Sammy). In Vamonos after Michael's failed escape, Lechero informs him that he will break out of prison, but with one catch—he must take Lechero with him. In the following episode Bang & Burn, Lechero reveals an underground tunnel which they can use to escape. in the episode Hell or High Water Lechero is shot by the guards during the Sona Escape. In the following episode The Art of the Deal T-Bag and Bellick come to Lechero's aid. T-Bag tells Lechero that the guards will let them go for 50,000 dollars. Lechero calls his girlfriend who brings T-Bag the money. After getting the money T-Bag takes his place as the leader of Sona by suffocating Lechero with a pillow while Bellick stands by and watches in terror.