“At Lyra’s funeral on Wednesday we heard many messages of the potential for a better future, but as I’ve said previously such sentiment will be all in vain if we can’t tackle the malign influences that some individuals continue to exert over our communities.” Lyra McKee was shot dead in Londonderry on April 18Credit:AFP “I think people in the community know who they are and I’m asking them today to come forward to help us.”Speaking about the main suspect, Mr Murphy said: “He is shorter than both of the other men and is of stocky build. “It is of my belief that he is the gunman that fired indiscriminately into the crowd and placed the community and police officers at risk.”I believe he is the person who took the life of Lyra McKee.”Mr Murphy said the PSNI has received widespread support from people in Derry, adding that they have the information to unlock details of who is responsible for Ms McKee’s death. Police investigating the murder of Lyra McKee have released footage of a suspect they want to identifyCredit:Justin Kernoghan/Photopress Belfast Detectives investigating the death of Lyra McKee have released the first images of her suspected killer, as they appealed for help to identify a stocky man believed to be armed with the murder weapon.The Police Service in Northern Ireland (PSNI) said they believe the identity of the suspect is known in Creggan, where the 29-year-old journalist was shot dead as she observed rioting on April 18.PSNI Detective Superintendent Jason Murphy said he believed residents on the Londonderry estate can “unlock the key” in solving the murder but suspected some were “frightened” to come forward. Mr Murphy released footage of three men, including the suspected gunman, walking in Creggan a minute before Miss McKee was killed, as he said: “I need the public to tell me who he is”.Mr Murphy said: “I’m releasing footage today from the night of Lyra’s murder and I want to appeal to anyone who recognises or knows these people to talk to us. He made a direct appeal to the gunman asking him to come forward and explain why he fired the shots and explain to Ms McKee’s family why she died.The suspect, who police believe to be aged in his teens, appears to be carrying the gun in his right hand in one of the images.Mr Murphy called on the community to overcome any fears and come forward to identify the main suspect.”I believe that people in the community know who this individual is. I recognise that people living in Creggan may feel it is difficult to come forward to speak to police,” he said.”Today I want to provide a personal reassurance that we are able to deal with those issues sensitively. “I need the public to tell me who he is.”I do believe the community has information that can help us unlock the key to Lyra McKee’s murder. I’m not sure individuals are protecting this person, but I believe they are frightened.”It has also emerged that forensic tests on the bullets fired suggest that a gun of a similar calibre has been used in previous paramilitary-style assaults in Creggan.”It’s symptomatic of the fact that weapons of this type are in circulation in Creggan and other areas of Northern Ireland and continue to bring misery every single day to these communities,” Mr Murphy added.He added that the gunman will carry a “very heavy conscience” over Ms McKee’s murder. Police released footage of three men seen walking on the Creggan estate a minute before Miss McKee’s deathCredit:PSNI/PA Miss McKee’s funeral was held at St Annes Cathedral in Belfast on Wednesday with political leaders in Britain and Ireland in attendanceCredit:Reuters More than 140 people have provided images, footage and other information to police, he said.”Such information simply gets me through the door but it doesn’t get me to the door of a courtroom. I need people to contact my team to talk to us about what they know,” he added.”Whilst the community information has been coming into us I have been keen to convert this information and intelligence into tangible evidence to allow us to bring this individual to justice. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.