Manchester bomber Salman Abedi, who killed 22 people at a city concert nine days ago, bought most of the components for the bomb himself, police said.
Many of the suicide attacker’s movements and actions were “carried out alone” in the four days prior to the attack, said Russ Jackson, head of the North West Counter Terrorism Unit.
But police were yet to rule out whether he was part of a “wider network”, Evening Standard reported on Wednesday.
Officers cordoned off a street in the Rusholme area of Manchester where a property was being searched on Wednesday.
Greater Manchester Police asked members of the public to avoid Banff Road, after the latest in a series of raids linked to their investigation.
Eleven people remain in custody for questioning following a series of raids across the country as three men — two aged 20 and 24 from the Fallowfield area and a 37-year-old from Blackley — were released without charge on Tuesday.
Updating the “huge progress” made in the inquiry, Jackson said: “Much of the investigation has been painstakingly working through Salman Abedi’s last movements.”
Officers have examined his movements on CCTV and other interactions he had with people as well as phone calls he made.
“With specialist support we have also have a good understanding of the likely component parts of the bomb and where these came from,” the head of counter terrorism unit said.
Jackson said police were “especially keen” to find out why Abedi, 22, kept going back to the Wilmslow Road area of the city as they continue to attempt to trace a blue suitcase he used during those trips.
Although detectives have no reason to believe the luggage contains anything dangerous, they warned the public not to approach it and instead call 999 immediately.
The police investigation moved into a different phase, with detectives trying to bring the various strands of information and evidence together to build a case against Abedi’s alleged co-conspirators.
Jackson said police will “take considerable time before we fully understand what has happened”.