|Profession:||Internal affairs agent|
|Played by:||Ian Tracey|
|Appeared in:||Insomnia (voice only)|
John Warfield was an internal affairs agent who was investigating Will Dormer and Hap Eckhart, two Los Angeles detectives. He started putting pressure on Hap Eckhart about brutality against some drug dealers, although he was really after Dormer. He offered Eckhart a deal to get him out of his charges by helping with the case against Dormer, and when the two were sent to Nightmute to investigate the murder of Kay Connell he asked Charlie Nyback to be informed of their movements.
Eckhart was killed in Nightmute, and Warfield tried several times to contact Dormer. When he got through, he said he would be very interested in hearing about what had happened to Eckhart, implying Dormer was behind the killing. Dormer grew angry, and started accusing Warfield of hiding behind a desk and sucking the marrow out of real police officers, before he hung up the phone.