Can a "cliche detective" be a suspect?

in detective movies, the detective’s job is to find flaws in the suspect’s aliases and whereabouts. the cliche for a detective is a guy who lives alone with no girlfriend, no parents, no friends (besides his new partner, who he just met and the partner knows nothing about him), drinks a lot, smokes a lot, carries a gun and sometimes does drugs alone in his apartment. he goes home after a long day and just goes to sleep/passes out. he usually has some sort of street connection. so, if the detective touched the murder weapon without gloves, couldnt he be a suspect?