When a disabled woman is found brutally murdered in her home, her neighbour is the prime suspect. Rhona Heywood was found dead next to her unconscious neighbour in 2008 after spending an evening drinking together. Martin Garratty claimed he had been asleep and had no recollection of murdering Rhona, but injuries to his face and hands, consistent with an attack, were enough to charge him with murder. At the trial, questions arose as to the nature of one of his injuries, a broken finger, suggesting it had occurred prior to Rhona's murder. As a result, the prosecution's case was put under scrutiny. A consultant doctor, Rowley Cottingham, was brought in to prove without a doubt that other injuries found on his face and hands were in fact made by his violent and deadly attack on Rhona. In our second case, a woman is being stalked and harassed by her ex-partner. He throws bleach over her belongings, trashes her car and sends threatening and abusive messages that leave her fearing for her safety. She goes to the police for help, but as all the abusive messages are anonymous, they don't have enough evidence to bring the ex to justice. However, when he begins to also write offensive emails to the police officer assigned to the case, this time from his own email account, investigators bring in a forensic linguist, Dr Nicci MacLeod, who specialises in analysing the construction and use of words in emails, letters and texts, to go through all of the communications. Using her expertise, she is able to show that the messages all came from the suspect, giving the police the evidence they need to close the case.