A typically Melvillean theme of trust and betrayal in the underworld features Serge Reggiani as an ex-con who suspects his best friend, Jean-Paul Belmondo, of being a stool pigeon. Melville was particularly proud of the 9 minute, 38 second shot in policeman Clain's office (an exact copy, Melville adds, of the office used in Rouben Mamoulian's City Streets, 1931). Melville's gangsters display their usual impassive, underplayed demeanor, increasing a sense of ambiguity in the characters in Le Doulos. “The characters are all double,” Melville notes, “they are all false. I even signal this...at the beginning of the film with that truncated line from Celine: ‘One must choose...Die...or Lie?' I cut the end, which is ‘Me, I live!'” His policemen have “that layer of cynicism and vulgarity which all policemen acquire after associating with crooks for a certain number of years.... In general I think my gallery of policemen...corresponds to a certain truth, even though I take care never to be realistic” (quoted in Rui Nogueira's Melville).