This is the fiend witnesses say gunned down an aspiring banker on the Lower East Side in January – and the slain man’s dad says the area isn’t safe with the gunman and his accomplice on the street.

Cops put a Manhattan man they arrested – and then released – through “hours of abusive interrogation” in connection with the Lower East Side slaying of a college buddy, his lawyer claimed yesterday.

Burke O’Brien was a strong guy, a former high school football star and an outdoorsman who spent his summers leading kids on canoe trips in the Canadian wilderness. His father said yesterday he was ...