The suspect I believe did NOT commit the murders is Joseph Barnett. There is no evidence to suggest Barnett could have, or would have wanted to, kill the five victims. Perhaps Barnett may have had a reason to kill his girlfriend, Mary Kelly, but not the other four women. Some research suggest that, in an attempt to scare Mary for prostituting, Barnett killed the other women. Yet there is truly no evidence that Joseph was a violent man, or the kind of man who would murder another person. Mary and Joseph had a few fights in the past, yet none were physical or were anything beyond yelling at each other. The only crime Barnett was ever known to commit was robbery; he stole a few pence from a fellow fisherman. He seemed to learn his lesson from this crime, because he never committed another offense that we know of.
Joseph just does not seem like the kind of man to commit such vicious crimes against anyone, never mind helpless women.