Innocent on ITV left many viewers divided over the possible identity of the killer on Monday night, but some fans think they have it sussed.
Sally Wright was convicted of the murder of Matthew Taylor, her 16-year-old student, five years prior to the series kicking off.
In the first episode, Sally was released from prison after new evidence proved she wasn't the killer as she was nowhere near the crime scene.
Sally had been accused of having an affair with Matty too while she was never charged for this.
The affair theory was backed by a former student at Sally's school, named Anna, who claimed at the time to have seen the pair kissing.
It was this evidence that pinned the crime on Sally because it appeared as though they had a fling - while they were also spotted having a row moments before his death.
Anna was lying though, with detectives now trying to work out why she would have made something like that up.
But many viewers think they've cracked the case, with several fans now convinced Anna is the real killer.
They have worked out a possible motive judging by the actions and comments of Anna in the first episode, and the trailer for the second episode.
She began making up lies about Sally threatening her to the police, saying she'd threatened to break into her home and smother her with a pillow.
She also claimed she didn't know Matty, yet a preview clip saw her emotional at his grave.
Anna is clearly more linked to this than she has claimed, and due to her dangerous lies some fans wonder if she might have killed Matty out of jealousy.
Perhaps she liked Matty herself, or there is the other theory that Anna was obsessed with Sally and killed Matty after fearing there was something going on between them.
Taking to Twitter, one viewer said: "Plot twist, Anna fancies the pants of Sally!"
Another agreed: "Anna fancied Sally, so lied about her and Matty, right?"
A third tweeted: "Anna did it I'm telling you," while another said: "Its gotta be Anna who killed him."
Innocent airs this week at 9pm on ITV.
