Police investigating the Manchester bombing freed three more people without charge, including the bomber's brother, and released more photos Tuesday as they worked to reconstruct the killer's final movements.
The May 22 attack at an Ariana Grande concert killed 22 people as well as bomber Salman Abedi, a Briton of Libyan descent. Police are trying to uncover clues about a suspected network that supported him.
Greater Manchester Police released photos of a white Nissan Micra seized in Manchester, saying "significant evidence" had been found inside.
Police appealed for anyone who saw the car between April 13, when its previous owner sold it, and April 15 — when Abedi left the U.K. — to contact detectives.
Police say Abedi returned to Britain from Libya four days before the attack. Detective Chief Superintendent Russ Jackson said "Abedi made repeated trips to and from this car" during those four days, "and we believe he was taking items from the car to help assemble the device."
Police also released a photo of a sports bag with a San Francisco 49ers logo, saying anyone who recognized it should contact them.
The team released a statement Tuesday, saying "The 49ers were disgusted to learn that a gym bag bearing the name of the team was found as evidence in association with the horrific act of terror that took place in Manchester, United Kingdom. Our hearts and prayers are with the innocent people who have been affected by this tragedy.”
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Police arrested a total of 18 people over the attack, but have released 10 of them without charge. Eight remain in custody.
Among those released was Ismail Abedi, the dead bomber's brother, arrested a day after the attack. A 20-year-old man arrested May 27 and a 33-year-old man arrested May 24 were freed without charge on Tuesday. Their names were not released.
The bomber's father, Ramadan Abedi, was arrested in Tripoli on May 24, along with another brother Hashim, who Libyan security forces said was "aware of all the details" of the attack.
The Islamic State group has claimed responsibility for the attack.
Meanwhile, more details emerged Tuesday of the three London Bridge attackers: a Pakistan-born failed customer service clerk with links to one of Europe's most prolific hate preachers, a Moroccan pastry chef whose partner said he once went swimming rather than see his daughter and an Italian man who told authorities he "wanted to be a terrorist."
At least two of the men were known to British intelligence and law enforcement officials, raising questions about whether anything could have been done to stop the attack, which began Saturday when the men drove a rented van into a crowd and then leaped out to stab people who crossed their paths. Seven were killed and nearly 50 wounded. All three of the attackers were shot dead by police.
British Foreign Secretary Boris Johnson said it was fair to ask how the attackers "slipped through our net."
Security has become a key issue in the run-up to Thursday's general election. British security officials said none of the men was considered violent, but they acknowledged the difficulty of predicting whether extremists will turn dangerous. The assault was the third attack in three months in which most of the assailants had been on authorities' radar at some point.
As the investigation expanded to look at how the men knew one another and whether they were part of a larger conspiracy, Pakistani intelligence authorities swooped Tuesday into the town of Jhelum, where Khurum Butt lived until the time he was 7, when he moved to Britain. His cousin, 18-year-old Bilal Dar, told The Associated Press that Butt's uncle was taken in for questioning. It was unclear if he was detained.
"Our family is hurt by what he did," Dar said in the town about two hours east of Pakistan's capital. "This has destroyed our family's pride."
Butt, 27, embraced radical Islam during his time in London and was once filmed in a documentary called "The Jihadis Next Door." In the film, he was seen with a group unfurling a black-and-white flag associated with the Islamic State group. The men were followers of Anjem Choudary, a preacher who was jailed for his support of the Islamic State and who once praised the Sept. 11 attackers.
It is thought that Choudary played a key role in Butt's radicalization, according to a British government official who spoke on condition of anonymity because he was not authorized to talk about the ongoing investigation. Choudary's now-banned al-Muhajiroun group was linked to one of Butt's alleged connections, Sajeel Shahid, according to the British government official who again spoke on condition of anonymity.
Shadid allegedly provided al-Qaida terror training to Mohammed Siddique Khan, one of the four suicide bombers who killed 52 people during London's morning rush hour in 2005. He was also accused of training other terror suspects in Britain.
During his time in Britain, Butt once worked for Transport of London as a customer service clerk but failed his probation after a few months on the job. He also worked at Kentucky Fried Chicken and used a gym in east London. In his spare time, he tried to recruit followers to the Islamic State group — a practice that prompted a neighbor to report him to the police in 2015.
He was one of about 3,000 suspects who were known to British authorities but not part of 500 active investigations.
"The problem occurs when we know someone is moving in extremist circles but we don't have evidence to indicate that they are plotting an attack," said the British government official who spoke on condition of anonymity. "That's where the question of resources comes into play."
Police identified the second attacker as 30-year-old Rachid Redouane, also known as Rachid Elkhdar, who claimed to have both Moroccan and Libyan roots and worked as a pastry chef in Ireland, where he had lived in the past five years as well the east London suburb of Dagenham.
He married a British woman named Charisse O'Leary, who posted on Facebook last month that Redouane was negligent in seeing their young daughter and on one planned visit, she said he told her: "I'm going swimming." The couple is thought to have split. O'Leary was one of 13 people arrested after Saturday's attacks. Twelve were later released. One man is still being held.
Redouane was never under surveillance by Irish authorities, and Justice Minister Frances Fitzgerald urged caution in speculating about his movements.
The third attacker was identified as Youssef Zaghba, a 22-year-old Italian national of Moroccan descent who was reportedly working in a London restaurant.
An Italian prosecutor says Zaghba told authorities after being stopped last year at Bologna's airport that he "wanted to be a terrorist," but then quickly corrected himself.
There was not enough evidence to arrest or charge Zaghba when authorities questioned him at the Marconi airport on March 15, 2016, Bologna prosecutor Giuseppe Amato said Tuesday. Amato told Italy's Radio 24 that Zaghba was flagged to British authorities as a "possible suspect."
Zaghba was stopped while trying to take a flight to Turkey on his way to Syria, Italian newspaper Corriere della Sera reported Tuesday.
After that, Amato said, any time Zaghba was in Italy, he was always tracked by Italian intelligence officers.
"We did everything we could have done," he said. "But there weren't elements of proof that he was a terrorist. He was someone who was suspicious because of his way of behaving."
Italy has expelled nearly 50 people in the past two years who were suspected of extremist activities but for whom there was insufficient evidence to bring formal charges. Zaghba's Italian citizenship prevented such an expulsion, Italian daily Repubblica reported.
His mother said her son used to show her videos of Syria and wanted to go "because it was a place where you could live according to a pure Islam."
Valeria Collina was quoted by Italian weekly news magazine L'Espresso as saying she last spoke to her son Thursday and now realizes it was a goodbye call. She said she tried to keep him away from radical friends, but "he had the internet and from there he got everything."
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 in 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.
The number of police officers in England and Wales fell by almost 20,000 between 2010 and 2016 — years when May, as home secretary, was in charge of policing.
The country's official terror threat level remains at "severe," one notch below the highest.