James Kelly is not Jack the Ripper

Jack the Ripper in America

James Kelly is known for the suspect of Jack the Ripper, the serial killer who killed prostitutes in late 1980. In the documentary, JAck the Ripper in America, a former head of NYPD cold case Squad, Ed Harris investigates the potential suspect of the serial killing which also occurs in America. The main suspects of his investigation is James Kelly. Why do he choose James Kelly:

1.   He is diagnosed of mental disorder
2. He is capable of murdering using knife
3. He killed his wife with a knife
4. He escaped from the mental institution before the white chapel killings
5. He went to USA and there are murders with same MO with jack the ripper

However, I don't think that he is Jack the ripper. Why first of all, there are no concrete evidence that James Kelly is in London on 1988. Next, as a serial killer, why should he what for 3 years just to do another serial killings? Why don't he just kills random people at london at that time?Why must America? Yes he kills his wife but that doesn't show any connection on the others killing. He kills his wife because she thought  her wife cheated on him. Yes he escaped from the mental institution, but why kill people when he can just run away?and there is no evidence that link James Kelly were in London when the murder occurs. Last but not least , he went to America and then accused to be the jack the ripper. There are others suspect that live in America, for instance, George Chapman, who killed 3 of his wives.There are also evidence that show Chapmans were in London when the white chapel killing occurs. The best part of the evidence is the letter. The handwriting of the Jack the ripper does not match James Kelly handwriting at all! Thus, what i can conclude is James Kelly is not Jack the ripper. The question  now is WHO?