In understanding the CIA's role in human rights, there are challenging problems of ethics. John R. Stockwell, a CIA officer who left the Agency and became a public critic, said of the CIA field officers: "They do not meet the death squads on the streets where they are actually chopping up people or laying them down on the street and running trucks over their heads. The CIA people in San Salvador meet the police chiefs, and the people who run the death squads, and they do liaise with them, they meet them beside the swimming pool of the villas.