While Pentiment does not have a canonical killer, meaning it wants you to decide who actually did the murders, the identity of the puppet master is revealed in the end. Here's who is the brain behind all of it.
There are a lot of suspects, and evidence to collect in order to find the culprit. However, if you want to know who is really behind it, we'll give you an answer below.
Obviously, this article is jam-packed with spoilers and will ruin the story and the ending so if you don't want to know these specifics, go away now. Perhaps read our review of Pentiment instead.
*HEAVY SPOILER TERRITORY*
If you still want to know who is behind the murders in Pentiment, you need to know that Pentiment will never tell you who the killer is. There is no canonical murderer so it's up to you to decide.
You'll investigate and find clues and based on that, make a decision on who is going to pay for the crimes. However, the game will tell you about the "thread-puller" or the person who is orchestrating these murders. Read on to find out who is the puppet master.
The person who is writing the notes with the beautiful purple font is Sister Amalie, who you may know as the female in the cell in the town's church who receives visions from God.
Sister Amalie is being manipulated by Father Thomas, who is basically telling her what to write. That makes Father Thomas, the thread-puller - the person who has orchestrated the murders by sending all those notes to people whose lives were destroyed by the Baron, in order to evoke an emotional response from them and eventually commit the murder.
That still doesn't make Father Thomas the murderer. Or perhaps it does? Who knows. Pentiment won't tell you that and it's up to you to find enough evidence and piece it all together.
Pentiment certainly is a very unique video game and it will probably take you several playthroughs before you get a clearer picture about the killings.