Inspector Hubbard: We just proved that you conspired to murder your wife and framed her for murder.
Tony: What?!? How in satan's hairy nutsack have you done that?
Inspector Hubbard: You had the key to unlock that door.
Tony: AND?
Inspector Hubbard: How else did you know where to find the key, and why was it there in the first place, unless you left it there for the murderor to find?
Tony: That was MONTHS ago. Maybe I put the key there as an emergency backup in case I lost my key. Maybe any one of a hundred things could have happened.
Inspector Hubbard: Well, why did you try and run off when you saw us all here?
Tony: Seeing three people who had somehow broken into my home freaked me out. ESPECIALLY when one of them is being executed tomorrow on evidence I gave in court and who should be in prison right now, one of them accused me of framing that person about an hour ago and the other listened to that framing story and could've been taken in by it. I decided to get out of there before you all tried to beat the *beep* out of me. Any more cockamamie hunches you want to throw my way?
Inspector Hubbard: Uhhh.
Tony: Yeah. Didn't think so. See you tomorrow at the execution bitches. Tony out.
Tony: That was MONTHS ago. Maybe I put the key there as an emergency backup in case I lost my key. Maybe any one of a hundred things could have happened.
Tony told the inspector that there were only two keys: one that he keeps in his pocket, and one that Margot keeps in her purse. If Tony is the one who knows about one of the keys being under the stair carpet then he must also explain how Swann's latch key ended up in Margot's purse. Anyway, something is obviously fishy and hence there's reason to stop the execution.
Tony would then admit he lied about there being only two keys. That was his only 'crime'. He could argue he kept the existence of the third key to himself because the wider knowledge of same would be an obvious security risk.
Swan's key ended up in Margot's purse because after she killed him, she took it out of his pocket and placed it there (mistakenly thinking it was hers), in order to cover up that she had provided him with her key so that he could let himself in quietly.
One of the main reasons why Margot was a suspect, is that there was no explanation how Swann could have entered the apartment on his own; therefore, Margot must have let him in somehow and the court doesn't believe Margot's story that Swann was an intruder. But if Tony kept a key under the stair carpet, then Swann could have let himself in by using that key, which means there is now much less reason to doubt Margot's story that Swann was indeed an intruder who attacked Margot in the middle of the night.
And why would Tony have worried that revealing the existence of the third key to the police might be a future security risk, when there has *already* turned up a dead body in his apartment of a dodgy guy who possibly attacked his wife and who had possibly used the third key to illegally enter his home? His wife was attacked *and* is going to face death penalty, and he worries about a "potential future security risk"? "Tony, where are your priorities, dude?" You see now how fishy that defense would look to Inspector Hubbard?
And whether or not a case could be made against Tony, it's at least obvious now that there is reasonable doubt about Margot's guilt.
Swan's key ended up in Margot's purse because after she killed him, she took it out of his pocket and placed it there (mistakenly thinking it was hers), in order to cover up that she had provided him with her key so that he could let himself in quietly.
Except Mark can testify that, right before the men were leaving the house to go to the club that night, Margot still had her key in her purse when Tony asked to borrow Margot's key.
Furthermore, in your proposed scenario, if Margot had taken Swann's latch key thinking it was hers, what had happened to Margot's own key then? Swann's body didn't have any other keys on him.
Sorry, the theories that your post proposes don't add up, and would be easily dismissed by Inspector Hubbard and the police.
You're absolutely right. And I am indeed thinking along your lines, but just contemplating the ifs as a devil's advocate, so to speak. In fact I anticipated some of your counterarguments:
if Margot had taken Swann's latch key thinking it was hers, what had happened to Margot's own key then?
Perhaps she simply misplaced it. She wouldn't have made any attempt to locate it as she didn't know it was missing. How could anyone prove otherwise? Who would have the onus of proof?
You see now how fishy that defense would look to Inspector Hubbard?
Fishy? Sure. Implausible? Yes. I'd go further and say it would look like a blatant lie and a desperate attempt to wriggle his way out of the corner he's just been craftily placed in. And you're right: he is allowing himself to be painted as an insensitive bastard or absent-minded twit, etc. if it means getting off the hook. But unless his defence can be disproved, I imagine (in this hypothetical alternative-ending scenario), Inspector Hubbard would in his professional capacity be obliged to accept it at face value.
But if Tony kept a key under the stair carpet, then Swann could have let himself in by using that key, which means there is now much less reason to doubt Margot's story that Swann was indeed an intruder who attacked Margot in the middle of the night.
Very true. I can imagine Mark interjecting at this point. Of course this version of events opens up another series of implausibilities (Swann would have guessed the existence and location of the spare key, Margot would again be probed as to why Swann's key was in her purse), but the mere possibility would likely be enough to save her.
However the point at issue was not the proof of her innocence, but the questionably manufactured 'proof' of Tony's guilt. I'll take the liberty of continuing with the hypothetical dialogue (see above). Feel free to offer corrections:
Tony: What are you people doing here?
Inspector Hubbard: We just proved that you conspired to murder your wife and framed her for murder.
Tony: What?!? How in satan's hairy nutsack have you done that?
Inspector Hubbard: You had the key to unlock that door.
Tony: AND?
Inspector Hubbard: How else did you know where to find the key, and why was it there in the first place, unless you left it there for the murderor to find?
Tony: That was MONTHS ago. Maybe I put the key there as an emergency backup in case I lost my key. Maybe any one of a hundred things could have happened.
Inspector Hubbard: Emergency backup, eh? How could it be that you didn't tell your wife about it?
Tony: I was afraid she'd disapprove on account of the security risk it would pose.
Mark: Do you realise what this means, Inspector? Swann may have used that very key to gain entry to the flat, meaning that Margot's claim that he was an intruder and she killed him in self-defence, stacks up.
Inspector Hubbard: Then for God's sake, Tony, why didn't you tell us about the key, could you not see that it would save your wife?
Tony: (very coy) As I said, I put it there months ago, subsequently forgot (since I never needed it), and only just now remembered.
Or Tony could have said that after Margot was taken away with her purse and key that he made another copy of the key and put it under the stair in case he locked himself out for whatever reason. Many people do that in real life.
Frankly, with a murder in the apartment, Margot's supposed key still in her purse somewhere at headquarters during the six months of the trial to execution, Tony if he had any sense would have changed the lock, especially since there is a question of how Swann got in. He should have wiped the slate clean, with a new lock, new keys.
Also, did anyone else notice that their door automatically locked upon closing? When Tony left the apartment that one time after meeting with the Inspector, he definitely just shut the door, and then a few minutes later the Inspector used Tony's key to get back in to the apartment. So Margot didn't even need a key to lock the door after Tony left for the stag party.