LONDON (AP) -- A new search was underway Tuesday in a neighborhood near the home of two of the London Bridge attackers, hours after police said they had freed everyone detained in the wake of the rampage that left seven dead and dozens wounded.
The attack, the third in Britain in three months, has raised questions over the government's ability to protect Britain following cuts to police numbers in recent years. The issue has become a key one in the run-up to Thursday's general election.
Prime Minister Theresa May, who called the snap election in hopes of strengthening her mandate for discussions over Britain's exit from the European Union, has come under fire for the cuts to police numbers over recent years. A string of opinion polls over the past couple of weeks have pointed to a narrowing in the gap between her Conservative Party and the main opposition Labour Party.
London police said all 12 people held since the attack late Saturday from the Barking neighborhood in the east of the city, have been freed. A new search was underway Tuesday in Ilford, just north of Barking, as authorities tried to determine whether the group had accomplices.
One of the attackers, Khuram Shazad Butt, had appeared in a documentary "The Jihadis Next Door" and was known to investigators but police said he was not believed to be plotting an attack. The second man, Rachid Redouane, had not aroused any suspicions. Police have not released the identity of the third. The three, who were wearing fake suicide vests, were shot dead during the attack.
The Islamic gym where one of the London Bridge attackers trained says they saw nothing of concern during his time there.
In a letter posted outside Tuesday, the Ummah Fitness Centre said staff would "help the police in any way we can" as investigators try to learn more about Khuram Shazad Butt, who was one of those who rammed a van into pedestrians on London Bridge and then slashed and stabbed people in nearby Borough Market.
Neighbors described Butt as an avid weightlifter and Transport for London confirmed he worked for London Underground in customer service before leaving last October.
London Mayor Sadiq Khan said questions would need to be asked about what the police knew about Butt. He has said cuts in the number of police officers have had an impact on the ability to prevent attacks.
Much of the area around London Bridge remained cordoned off as commuters struggled to work in the driving rain.
The area around Borough Market is not expected to reopen Tuesday.
The nearby London Bridge station was operational though one of the exits that leads to the cordoned off area on Borough High Street remained closed.
Transport for London, which oversees the capital's transport network, has advised commuters to make alternative journeys as the station will be busy.
A minute's silence was observed in Britain at 11 a.m. local time (1000 GMT) in memory of those killed during the attack.
Questions remain over whether investigators had the resources to look into complaints such as those leveled by Butt's neighbors about his attempts to radicalize children and whether crucial opportunities were missed that could have saved lives.
Saturday's attack was the third in as many months involving suspects who had been on the radar of British authorities. All three have been claimed by the Islamic State group.
The country's official terror threat level remains at "severe," one notch down from the highest.
It had been set at "critical" in the days after the Manchester concert bombing on May 22 that killed 22 people — reflecting a judgment that an attack might be imminent because accomplices with similar bombs might be on the loose.
It was lowered once intelligence agencies were comfortable this wasn't the case. Authorities have said the London attack was apparently unconnected to the Manchester bombing.