Oh, I see. You're not as far into the case as I thought then - sorry if that caused any confusion.
So now you're trying to see if it's possible that the victim locked the door himself. Turns out it's not. Go through each of the options Torin suggests for when he did so and show evidence to prove it's impossible.
That's strange. You're only supposed to get the "blind trust" line if you've completed the killer route and not the victim route. Are you sure you've proved everything in the victim route (before he was shot, when he was shot, after he was shot) impossible on the same savefile?
You know that you've completed the victim route if you get this dialogue:
Riley:
"He couldn’t have locked the door before he was shot…"
"… after he was shot… … right when he was shot…"
"… He couldn’t have locked the door at all!"
Torin:
"That’s right. It’s impossible for the victim to have locked the door."
Right after this.
Also yes, I am playing the older version, I quite like it.