West Midlands police have released CCTV of a man they are seeking after a series of stabbings in Birmingham city centre left one man dead and seven people injured, two seriously. The attacker responsible for the stabbings – which happened in four different areas over a two-hour period in the early hours of Sunday morning – was still at large, police confirmed. Officers declared a major incident after being called to reports of a stabbing at about 12.30am on Sunday, with “a number of other stabbings” happening between 12.30am and 2.20am. On Sunday evening, Ch Supt Steve Graham of West Midlands police said: “We have worked throughout the day to trawl CCTV footage and speak to witnesses to ensure we release the best possible video and image of the man we want to speak to. At this stage we believe that the attacks were random and we have no indication of a motive. I would urge people to remain vigilant and report any suspicious behaviour to us. We are appealing for anyone who recognises the man in the footage to contact us urgently.” Police later said there had been a “strong response” to the video. Officers said there were four separate stabbings, beginning in Constitution Hill just north of the city centre, before the attacker travelled south and struck again in Livery Street, Irving Street and Hurst Street. The attacks were being considered as a “linked series”, said Graham, although the victims were unrelated. Police said a 23-year-old man suffered fatal injuries in Irving Street. A man, 19, and a woman, 32, were critically injured, and five other people aged between 23 and 33 were also injured. They were treated in hospital and so far two have been discharged. Savvas Sfrantziz, 64, the manager of Mykonos, a bar and grill on Hurst Street, told the Guardian he thought he had witnessed one of the attacks. “This was completely random and I have never seen such violence on Hurst Street,” he said. Sfrantziz said he had heard noise outside and went to investigate, then saw a woman being stabbed repeatedly. He said the perpetrator did not seem to know her and seemed relaxed. “I heard a lot of noise outside and went to investigate. I saw a young woman in her early 20s stabbed in the neck seven times. The perpetrator did not know her, and he seemed relaxed. He didn’t care. People didn’t go near him. I’m not sure if he was on drugs or if he was 100% there. He was not acting clever. “It was very busy here. People were happy and enjoying themselves. There is hardly any violence in Hurst Street. It is usually the nearby bars of the Arcadian where fights break out regularly.” Graham said the events were “tragic, shocking and understandably frightening”. Officers were seen removing a black-handled kitchen knife from a drain, but Graham said it was too early to say whether the knife was connected to the murder inquiry. He added: “Already we’ve got people going down drains, we’ve got that level of detailed searches taking place which will hopefully reassure the people that we are doing everything we can do to trace the offender.” Graham said there was “absolutely no suggestion” that the stabbings were terrorism-related. One of the incidents happened close to Birmingham’s Gay Village, but Graham said there was also no evidence the stabbings were linked to hate crime. Nathan Hudson of West Midlands ambulance service said 14 ambulances were sent to the city centre at about midnight. Hudson said the crews were used to dealing with stabbings, but there had been an added element of anxiety. “We knew we had an attacker with a knife, going around randomly stabbing people,” he said. “We had an ongoing incident and we didn’t really know at what point that would end.” There was a heightened police presence in the city centre on Sunday, with significant sections of the affected areas cordoned off and forensics tents erected by police. David Nash, bar manager at the Village Inn, the Nightingale Inn and the Loft Lounge, told PA Media he had come within 10 metres of a suspect spotted running from the scene of the stabbings in Hurst Street. “I was on the street and we heard somebody shout down the street: ‘Stop him, he’s just stabbed somebody,’” he said. Nash said the person was “calm” and walking unhurriedly, until the person shouted, at which point he started running. One resident who had turned up to work at PureGym near Hurst Street was sent home because he could not cross the police cordon. The man, who did not want to give his name, said: “I didn’t imagine it would be this bad. Stabbings happen unfortunately all the time but it looks like it’s worse than anything that’s happened so far. Nowadays Birmingham is dangerous, especially the city centre. I’m not really surprised. It’s something that is basically happening on a daily basis in Birmingham, stabbings and other violent crime.” The prime minister, Boris Johnson, tweeted his thanks to the emergency services: “All my thoughts are with those affected by the terrible incident in Birmingham last night.” The home secretary, Priti Patel, said her thoughts were with people affected by the “shocking incident”. She tweeted: “Our emergency services are working hard to find whoever is responsible and bring them to justice.” Liam Byrne, Labour MP for Birmingham Hodge Hill, said: “This was shocking violence which we just won’t accept in our city. Once again our emergency services did an incredible job running towards the danger. Now we need to get behind the police to catch the perpetrator of this senseless crime.” The West Midlands police and crime commissioner, David Jamieson, said: “Last night’s events are truly terrible and have shocked the people of Birmingham, the West Midlands and the country. My first thoughts are with the victims and their families at this time. “I have every faith in West Midlands police, who are working extremely quickly on this investigation. My thanks also go to the ambulance and hospital staff who are working around the clock to help those who have been injured.” Jamieson said a rise in violence was “almost inevitable” as a result of the pandemic, with people “not being able to get out, and combine that with people who are now unsure about their future and about their jobs”. He said he was not directly relating the incident to the pandemic, but said there was “now a growth of violence among younger people, particularly younger males, we’re seeing that growing across the region”.