British police on Saturday released surveillance-camera images of the Manchester suicide bomber on the night of the attack as they appealed for more information about his final days.
Authorities said they had made major progress in unraveling the plot behind the bombing but acknowledged there were still gaps in their knowledge.
Britain reduced its terrorism threat level a notch Saturday, from “critical” to “severe,” yet security remained high as jittery residents tried to enjoy a long holiday weekend. Armed police officers and soldiers were deployed at big events.
Abedi, a 22-year-old Briton of Libyan descent, died in Monday’s explosion, which killed 22 others and wounded nearly 120 as crowds were leaving a concert.
The photos released by police show terrorist Salman Abedi on the night of the bombing, wearing sneakers, jeans, a dark jacket and a baseball cap. The straps of a knapsack are visible on his shoulders.
Greater Manchester Police Chief Ian Hopkins and Neil Basu, the national coordinator of counterterrorism policing, urged people to contact police if they had information about Abedi’s movements between May 18 and Monday night.
“In the past five days, we have gathered significant information about Abedi, his associates, his finances, the places he had been, how the device was built and the wider conspiracy,” they said in a statement. “Our priorities are to understand the run-up to this terrible event and to understand if more people were involved in planning this attack.”
British Prime Minister Theresa May said “a significant amount of police activity” and several arrests had led to the level being lowered. But she urged Britons to remain vigilant and said soldiers would remain at high-profile sites throughout the weekend, and start reducing their presence beginning Tuesday.
A severe threat still means an attack is “highly likely,” according to the scale set by Britain’s Joint Terrorism Analysis Centre.
Assistant Commissioner Mark Rowley, Britain’s top counterterrorism police officer, said authorities have dismantled a “large part” of the network around bomber Salman Abedi.
But Rowley said there were still “gaps in our understanding” of the plot, as investigators probed Abedi’s potential links to terrorists in Britain, Europe, Libya and the Middle East.
“There will be more arrests and there will be more searches,” he said.
Police made two more arrests in Manchester on Saturday on suspicion of terrorism offenses, bringing the number of suspects in custody to 11. All are men, aged between 18 and 44. In addition, Abedi’s father and younger brother were detained in Libya.
Police disclosed new details about Abedi’s movements, saying he returned to Britain four days before the attack. His father has said Abedi was in Libya until earlier this month and had told the family he planned to go to Saudi Arabia on a pilgrimage.
Police say they think Abedi assembled his bomb at a rented apartment in central Manchester that was raided by officers Wednesday.
Investigators have searched 17 properties, including Abedi’s home in south Manchester and other houses in nearby districts.
Residents were evacuated from streets in the south Manchester neighborhood of Moss Side in what police called a precaution as one search was carried out Saturday. Photos showed an army bomb-disposal unit at the property.
Another place searched was an apartment in a Manchester high-rise that British media say was rented by Abedi in the months before the attack. Mohammed El-Hudarey, a friend of the landlord, said after Abedi moved out about six weeks ago there was a strong smell of chemicals and debris including metal rods and cut-up fabric.
Britain’s health service said Saturday that 63 people wounded in the bombing remain hospitalized, 20 of them in critical condition.