I guess Kimble had a lousy attorney
This is one aspect of the film that always bugged me. A good lawyer would have pointed out that Helen could have easily meant "Richard, he's trying to kill me" rather than "Richard...he's trying to kill me" or that she could have easily been coerced into saying that by the intruder. Either one of those would have ensured reasonable doubt, all of which needs to be removed to convict one of murder. I doubt a doctor couldn't afford a better attorney.
Feminism dismantled: https://m.youtube.com/watch?v=a2bvAMj-GLc