they marry. Sinead is worried when baby Katy falls ill and takes her to the hospital. Lindsey accuses Sinead of lying about Katy being ill for attention and misdiagnoses her, discharging the infant from the hospital. Infuriated, Sinead puts blood in Katy's nappy which had come from a cut on Sinead's finger to ensure that she is diagnosed properly by a doctor, but later admits the truth to Diane. Social services takes Katy away from Sinead and Diane becomes her foster mom. However, when Diane is arrested for possession of drugs during her wedding to Tony Hutchinson (Nick Pickard), Sinead is allowed by Finn to see Katy whilst he is out of the room. Shortly after Sinead leaves, Diane returns and discovers Katy convulsing in her cot. Katy is rushed to hospital whilst Sinead is arrested for assaulting Diane, and Freddie informs Sinead that Katy is in intensive care. Sinead steals a car after being cautioned at the police station to get to the hospital, but Fraser Black (Jesse Birdsall) crashes into Sinead and leaves her trapped inside her car. Luckily, Sinead is found and is taken to the hospital, but Freddie informs her that Katy has died. Sinead is put on a psychiatric ward as Finn confesses that Sinead was alone with Katy before she was rushed to hospital and everybody, including Diane, believes Sinead poisoned Katy in a bid for attention however it is revealed at Katy's funeral that Katy really was ill and Sinead had nothing to do with her death. Sinead leaves Freddie because he didn't believe that she didn't hurt Katy. In May, she finds out about Sonny Valentine's (Aaron Fontaine) part in the death of Superintendent Marlow (Paul Clayton). She threatens to tell the police unless Sonny helps her get back at Lindsey. After injuring herself, she goes to the hospital with Sonny where she is treated by Lindsey. Lindsey tries to sympathise with Sinead while treating her, but only causes her to get angrier. Sinead slaps Lindsey, then pushes her over, causing a syringe to enter her. Sinead then announces she is HIV positive. Believing her claims, Carmel Valentine (Gemma Merna) organises an AIDS charity event during which Joe arrives and reveals Sinead has been lying to make Lindsey suffer. Sinead decides that she needs to punish Lindsey and make her pay for "killing her baby". Sinead steals a car from Freddie's work