Maybe "a friend who was a hard case" (although that could just be someone who was a criminal without being violent). Maybe "vicious" or "savage" or "sociopath" would probably be better adjectives in English, given the guys we're talking about anyway. "Un hombre duro" or "profugos duros" doesn't translate directly the same in English as used in Spanish in the case being discussed. For example, "a hard man" (aside from sexual connotations - come on Rich One! Get your mind out of the gutter
) in English means more like someone who can be difficult to deal with, set in his ways, obstinate, even "a tough guy" (which doesn't necessarily mean someone who would kill or harm indiscriminately, rather someone who is prideful and is willing to stand his ground even against the odds, although can also mean gangster, which might be appropriate in this case)
