Casey Carswell Kim " K . C . / Casey " Carswell was one of the women Claire Peacock met through her voluntary phone counselling ; she had lost her baby . She had previously noted to the police that her nickname was K . C . not Casey , using the first letter in her first name and second name respectively . On 1st April 2007 , Claire left Casey with her newborn son , Freddie , while she went out . When she returned , she saw Freddie and Casey were not there . Claire panicked and called the police , thinking that Casey had kidnapped him . However , it transpired that Casey had taken Freddie out for a drive . A distressed Claire confronted Casey who became upset upon hearing that Claire had called the police . Casey , feeling upset , drove away just as the police arrived . However , in June , Casey was seen stalking Claire , and was believed to be responsible for the fire at 4 Coronation Street . When her photograph appeared in the " Weatherfield Gazette " and on the news , she went to the police voluntarily but was later released due to lack of evidence . She then confronted Claire . Casey and Claire resumed their friendship and Casey showed an interest in Claire ' s husband Ashley after Claire said she felt her marriage could be on the rocks . On 30th July 2007 , Casey made her move on Ashley . The pair were about to sleep together , however , they were interrupted and almost caught out when Claire arrived back from counselling unexpectedly . Audrey Roberts , ( a friend of Ashley ' s late father ) who was concerned about Ashley and Claire ' s marriage , saw Casey begin acting as wife to Ashley and mother to Joshua , while Claire was away ( on Casey ' s advice ) . Audrey confronted Ashley , who confessed that he ' d been sleeping with Casey and that Claire didn ' t seem to realise his needs anymore . Ashley told Casey that Audrey knew about their affair and Casey barged round to the salon and confronted Audrey . Audrey told Casey to stay out of Ashley ' s marriage and that she was just a fling that Ashley would get over . However , Casey stressed that she and Ashley were a proper couple and lied , saying that her affair had been going on for months . Audrey told Casey she ' d betrayed Claire as a friend and that the affair was her way to get revenge . Casey responded by implying that she , Ashley and Joshua would soon be a proper family and neither Audrey or Claire would be able to prevent it . Later , Audrey urged Claire to return home , which she did . After lots of silent phone calls , Ashley finally ended his affair with Casey , but Casey insisted she was the one in control and was convinced that Ashley secretly loved her . Claire was shocked to learn that Casey had been visiting the Peacock house , helping out with Joshua and cooking Ashley his dinner and , on top of that , she was sleeping there . Claire was suspicious and , along with a nervous Ashley , told Casey to leave . Claire asked Ashley if he was sleeping with Casey but he lied and denied the claim . Casey then went to Audrey and told her that she pushed Ashley to break Claire ' s heart and reveal that they were an item . Later , Claire invited Casey to lunch and Ashley told her to stop stalking him . Casey relished telling Ashley that she was not going anywhere . Casey continued to stalk Ashley for some time . One particular day she spotted a chance to draw his attention when he left Freddie in the care of Kirk Sutherland . Casey grabbed the opportunity , telling a gullible Kirk that Ashley had asked her to pick up Freddie . She went on to incorrectly inform Audrey that she and Ashley were a couple and would be getting married . Ashley ' s return greeted him with the news from Kirk that Casey had taken Freddie , much to his shock and distress . Ashley phoned her as requested and headed to her flat , insisting Kirk not tell Claire what was occurring . Audrey informed Claire of Casey ' s strange behaviour and Kirk told Claire that Casey had taken Freddie , despite Ashley telling him not to tell Claire . She and Audrey rushed to Casey ' s flat , meanwhile calling the police . Ashley ' s arrival at the flat surprised him , as he was greeted to walls covered with photos of himself and saw Casey on the balcony , holding Freddie . Casey then admitted starting the fire , explaining that she felt Claire was in the way of their love . Ashley , realising just how insane his " mistress " was , tried to convince her that what she was feeling towards him was imaginary . Casey , taken aback by Ashley ' s words , moved closer to the edge of the balcony clutching Freddie , saying if Ashley didn ' t love her , she and Freddie may as well be dead . Claire stormed into the flat to find close friend Casey nearing towards the balcony edge with baby Freddie . Casey forced Ashley to tell Claire the truth about their affair and that he was in love with Casey and that they had slept together while Claire attended her support group . Claire was silent and in deep shock , Casey went on to ask Ashley to propose to her ; scared and confused , Ashley did and Casey was elated with joy , but Claire challenged her . Claire described what Casey told her and how she felt at the death of her baby " Rhys " , about all the hopes she had and how she imagined her baby as he would grow up . Casey , now irritated , ran toward Claire in an attempt to stop her talking , allowing Claire to take Freddie but this made her run to the balcony and attempt suicide by jumping . Ashley managed to stop her just as the police burst in to arrest Casey . A couple of days later DI Parks , the officer assigned to the case , visited the Peacocks and told Ashley and Claire that Casey was mentally unfit to stand trial . She would be sectioned under the Mental Health Act indefinitely as she was a serious danger to other people . List of appearances . 2007