Captain Burke is on the phone at the photography studio and tells his assistant that the murder victim worked as a photographer in a night club. Nobody had mentioned that before. It is only later when the Landlady and Burke's girlfriend mention it that the police know this.
Captain Burke turns the ignition key of the Duesenberg to try to start the old car. The first ignition keys that also operated the starter mechanism were introduced by Chrysler in 1949. Duesenberg went out of business in 1937.
The Medical Examiner said that the victim's lungs were "full of carbon monoxide." If Eleanora had died of carbon monoxide poisoning her lips and/or skin would have been a cherry red at the time she was found on the electric chair. This unusual skin coloration would have been apparent to all those present. This cardinal sign of CO poisoning would have been immediately apparent to the Medical Examiner.