HAHA...way to post a halfassed explanation on a thread for a movie you weren't even really "paying attention to"....thanks for the excellent contribution lol
The answer is yes, they did torture the innocent man.
There were two men in the van, unbeknownst to them, and coincidentally, they were of similar build and looks. The couple found the man, who had flown out of the van when it crashed and assumed that he was the killer of their son, whilst the real killer made his escape.
Towards the end of the film, the police force track down the killer, and you see him being caught by them in the forest. The couple return to the house to find that the man charged with tax fraud (who they had tortured) had hung himself.
As for your question, there are two possible explanations for the man's note: 1) He did not want the couple to realise that he was innocent, saving them from the guilt for the rest of their lives. 2) His head injury from the crash caused amnesia, and given the stress of the torture, he eventually concluded that he was in fact the murderer of their son (although he could not recall it).
Either way, the parents will find out via television news or the police department that the killer has been captured. You may be wondering how the second reason can be true, if the innocent man knew the son's name, "Benjamin". However, since the man was travelling with the killer before, and that the couple had been talking about Benjamin upstairs (and perhaps also in the basement), it is quite possible that he could have found out their son's name.
Yeah, thanks, that helps. I'm more for the second theory. Not sure you'd want to spare them any sort of guilt after torturing you for no reason. He probably ended up believing he had been the one who killed Benjamin.
the reason the man knew their son's name is because while the father was torturing him, he actually said something along the lines of "my son, Benjamin." seems likely that he said his name under the extreme pain of torture, if he didnt actually no the name he might have screamed out a different one just to try and make them stop.
I think your answer #2 is pretty accurate. I spent a lot of this film wondering where they were going with this and then when I saw the twist I was confused why the guy would confess. I think the point of the film is if you torture anyone they will do, feel or say anything you want them to after awhile. They were never going to get any real remorse or any satisfaction. They themselves were the "tortured" and their pain was the loss of their son.