Peter Elliot is a Special Service Special Agent who works in the Secret Service's Financial Crime Division, Agent Elliott had an obvious infatuation with Calleigh Duquesne that interested her, but she stopped short when she found out, after taking him to the hospital for a gunshot wound, that he was engaged to another woman.
At the end of the season, it was revealed that his fiancée, Monica West, was the one that impugned the CSI lab and stole drug money seized in a raid; she caused the FBI to investigate, hoping that discrediting the lab would help her out politically. Elliot, wearing a wire, got her to confess, and she is arrested (episode 425, "One of Our Own").
He is played by Michael B. Silver.