As Perry comes through the door the first time he goes to the Balfour mansion, his shadow can be seen on the obviously painted outdoor scene in the background.
(At about 8:00): When "Fred Haley" drives up in his Jeep to witness the "hit and run", he stops at a Stop sign, which is a single sign facing the camera: the wrong way to be seen by a driver.
In the beginning scene at the train station, they are shown pulling into what is meant to be a remote country town. But when Harriet gets into a taxi to leave, it is a "Yellow Cab" whose phone number has a "MAdison" prefix: typical for Los Angeles at the time, but out-of-place in the "country".
At the end when Perry was questioning the witness, he asked her "Did you not kill your husband?" She answered "Yes!" This would mean she did not kill her husband. The writers either messed up or Raymond Burr did.
Early in the episode, when Harriet leaves the cabin, the cameraman (who is wearing glasses) is reflected in the car window as Harriet drives away.
The character posing as "George Egan" is eventually disclosed not to have died in the cabin where he was supposedly shot. However, Mrs. Balfour, who had arrived at the cabin by cab, drives away in the car leased to "George Egan", and Lawrence Balfour drives away in his own car - both returning to their own house. How then, does the character posing as "George Egan" return to his own apartment to receive the phone calls he is later revealed to have received?
Early in the show, Harriet Balfour sees her husband Lawrence off at the train station and takes a cab to a remote motel to meet her lover "George Egan." (The viewer will discover, later, who "Egan" really is.) She leaves to go home and establish a cover for her infidelity, planning to return in a short while. She drives off, passing right by her husband's car without seeming even to notice it - mere feet away.
Why did the DA suddenly decide to exhume the body? The trial was over. Apparently even though hit and run is a crime. There was no autopsy. The DA can't just decide to exhume a
body. He has to prove to a judge there is a solid reason to. And then he has to get permission from the family. It's hard to imagine a case so badly bungled as the first trial. On both sides.