The Metropolitan Police in London, who lead counter-terror policing operations, declared the assault a terrorist attack. Assistant Commissioner Laurence Taylor said two other suspects were arrested, though he provided no further information on the arrests. The attack took place as people gathered at an Orthodox synagogue in suburban neighborhood of Manchester on Yom Kippur, the day of atonement and the most solemn day in the Jewish calendar. A bystander could be heard on the video saying the man had a bomb and was trying to detonate it. Manchester was the site of Britain’s deadliest attack in recent years, the 2017 suicide bombing at an Ariana Grande concert that killed 22 people.