MANCHESTER: A British minister said on Sunday that members of the suicide bomber Salman Abedi’s network could still be a large, as thousands defied the terror threat to take part in an annual half marathon. As runners pounded the streets of the northwestern English city, police arrested a 25-year-old man in the eastern Old Trafford area, bringing the number now detained on UK soil in connection with the attack to 12. Manchester-born Abedi, a 22-year-old of Libyan origin, killed 22 people on Monday evening when he targeted a pop concert by US singer Ariana Grande. A third of those slaughtered were children and another 116 people were injured. Asked if some of Abedi’s network were still at large, British Home Secretary Amber Rudd said: “Potentially.” “The operation is still really at full-tilt in a way and so until the operation is complete we can’t be entirely sure that it is closed.” Authorities in Libya have detained Abedi’s brother and father, while British investigators appealed to the public late Saturday for details of the bomber’s movements in the days before the attack, which has been claimed by the Islamic State group. Police released photographs from security cameras showing Abedi on the night of the massacre, wearing jeans and trainers, a black bodywarmer and a baseball cap, with the straps of his backpack visible on his shoulders. The police statement said one of the last places he went to was a “city centre flat and from there he left to make his way to the Manchester Arena” where the attack took place. “The flat is highly relevant as a location which we believe may be the final assembly place for the device.” Security was highly-visible as 40,000 runners took to Manchester’s streets for the Great Manchester Run a day after Prime Minister Theresa May lowered the terror threat level, which was hiked following Monday’s carnage. Competitors gathered at the start line and fell silent as the clocks struck 9:00 am (0800 GMT). This was followed by sustained applause as the song “Don’t Look Back In Anger” by Manchester band Oasis was played over the tannoy, sparking a sing-a-long. ”After everything that’s happened in Manchester, to get everyone to come together, stand united, don’t let them win, that’s why I’m doing it,” runner Ian McLellan, 45, said. British counter-terror chief Mark Rowley said Friday that police had captured “a large part of the network” linked to the bombing. Investigators say they have a 1,000-strong team working “around the clock” on the probe and have significant details on Abedi’s associates and movements, his finances, and how the explosive was built. Britain on Saturday reduced its terror threat level from critical — its highest level — to severe. “We should be clear about what this means: A threat level of severe means an attack is highly likely, the country should remain vigilant,” Prime Minister May said. Operation Temperer, which involved the deployment of troops on patrol alongside police, will be wound down on Monday night, at the end of the bank holiday weekend. “From midnight on Monday, there will be a well-planned and gradual withdrawal of members of the armed forces, who will return to normal duties,” the premier said. May has seen her polling lead against the Labour party’s Jeremy Corbyn dwindle as campaigning restarted ahead of a June 8 general election, with her rival accusing her of overseeing a cut in police staff while she was interior minister. Authorities are currently handling 500 terror-related investigations into 3,000 individuals, with another 20,000 people on the radar posing a “residual risk”. May attempted to hit back late Saturday, announcing the new “Commission for Countering Extremism” and saying that “enough is enough — we need to be stronger and more resolute in standing up to these people”.