Keith Willets Police Detective Sergeant Keith Willets and his colleague DC Leslie investigated the blaze at the Rovers in March 2013 that killed firefighter Toni Griffiths and injured Sunita Alahan and Stella Price although both were rescued and taken to Weatherfield General , Sunita in a critical and unconscious condition . The fire had been started deliberately by Stella ' s ex - partner Karl Munro in revenge for her refusing to take him back after he began an affair with Sunita , which itself , only lasted for a short period . Sunita had followed Karl into the almost - empty pub and found him what he was up to . When she confronted him , a tussle broke out which culminated in Sunita being thrown down the cellar steps and left to her fate as the blaze took hold . Willets and Leslie turned up at the hospital after forensics discovered the deliberate nature of the fire . They visited Stella ' s beside and , in front of a nervous Karl , told her that they were now conducting a murder investigation . The Price family wondered if the culprit had been Sunita who had been on bitter terms with Stella but their accusation , when put to Dev Alahan by Willets and Leslie , caused him to flare up , thinking that his separated wife ' s reputation was being traduced . Jason Grimshaw , who at the time of the fire was in his own relationship with Stella , suspected Karl from the start and passed on his concerns to the police . He told them his own builder ' s van had been torched and it was undoubtedly Karl who was the culprit . Willets and Leslie duly interviewed Karl but he came up with plausible answers to their questions . Their next course of investigation was how the arsonist had gained entry . There was no sign of any break - in on the doors which suggested that he had used keys . All of the sets to the Rovers were accounted for except the spare set which was kept behind the bar . Karl himself was in possession of these and , knowing that the police were looking for them , planted them in Sunita ' s hospital bedside cabinet . They were duly found when Willets and Leslie searched the patient ' s belongings , shocking all concerned . Karl ' s plans looked like succeeding until Sunita showed signs of regaining consciousness . Desperate men do desperate things and Karl committed cold - blooded murder , disconnecting Sunita ' s life - support equipment before she could be questioned . The post - mortem on Sunita showed that she died as a result of smoke inhalation and more than likely , pulled out her own ventilator tube . Willets told a devastated Dev that they were closing the investigation . Dev conducted his own inquiries and in June called Willets to 7 Coronation Street to present him with the results . Most of these were his views on Sunita ' s character and how it clashed with that of the profile of a person who would be an arsonist and a murderer . Willets was unimpressed and told Dev to stop beating himself up over the matter . Karl ' s downfall came through the unlikely figure of Craig Tinker . Just before the fire he had been trying an illicit cigarette in the back yard of the pub . He also saw Karl leaving the premises and Karl discovered this fact . He terrorised the young boy with threats against him and his mother Beth but Dev saw the two in frequent conversation and started to put his own pressure on the boy . Craig admitted to Dev , Beth and Kirk Sutherland about the cigarette in the yard but they explained to him in turn that the fire started in the cellar and they concluded that it was Karl who was the real killer . Jason took Craig to the police station to make a statement while Dev ensnared Karl in the pub . The pair began to fight and Dev was knocked unconscious . As Stella arrived at the pub and witnessed an injured Dev on the floor , Karl revealed all to her . The police arrived as Karl threatened start a fire behind the Rovers bar . In his final moments as a free man , Karl held Stella in the pub ' s cellar but she managed to persuade him not to keep running and he was subsequently arrested by Willets . The final act in the drama was when Willets visited Stella and told her that Karl had made a full confession . List of appearances . 2013