U.K. police confirmed Wednesday that they are now investigating a "terror network" in connection to the attack Monday night in Manchester, England, that killed 22 people. "This is a network that we are investigating," Chief Constable Ian Hopkins of the Greater Manchester Police told journalists Wednesday. "There's an extensive investigation going on, and activity taking place across Greater Manchester as we speak."
Salman Abedi, the 22-year-old man who is believed to have exploded a suicide bomb at an Ariana Grande concert, was known to British intelligence and security agencies "up to a point," British Home Secretary Amber Rudd said. On Wednesday, police made a fifth arrest in connection to the incident.
The U.K. on Tuesday increased its terrorist threat level to "critical," the highest possible level, for the first time in a decade. The designation means a terror attack is considered "imminent" and allows for up to 3,800 military personnel to be deployed instead of police officers at public events.