Q: Passage: In a deserted car, Michael discovers the body of the man he planted the GPS tracker on and a badge revealing he was an FBI agent. Sabotaging the air conditioning in the train except for the last car, Michael forces all of the remaining passengers into the last car. He realizes another passenger, a musician, killed the FBI agent; he also received the same deal for $100,000, but with instructions to kill Prynne. Michael and the musician fight, at which point the musician is thrown from the train and killed. The real "Prynne" is revealed to be a young girl named Sofia, who is holding incriminating information on powerful people and was to go into witness protection at the final stop of the train. Michael asks Sofia why she did not go to the police. She reveals that it was the police who killed Enrique, who was Sofia's cousin.

Question: Based on this passage, who killed the fbi agent in the commuter? Let's give stream of consciousness first:
The important part for answering this question is: He realizes another passenger, a musician, killed the FBI agent; he also received the same deal for $100,000, but with instructions to kill Prynne. Therefore, the final answer is a musician.