Anti-terror police raided more homes on Monday as the relentless search for the network behind the suicide bombing continued a week on from the deadly attack.
Early morning raids were carried out at a house in Manchester, along with searches carried out in Chester and Shoreham-by-Sea, on the south coast of England.
A 23-year-old was held in the small seaside town on suspicion of terror offences in the early hours of Monday morning, Greater Manchester Police (GMP) said.
Violet Mainda, who owns a hairdresser's salon beneath the flat where he was arrested, said she believed the man who lives there was training or had trained to be a pilot, adding: "He was a normal bloke, very jovial."
As the police operation continued more questions were being raised about possible security and intelligence blunders surrounding what was known about bomber Salman Abedi.
With the massive operation to dismantle his terror network showing little sign of slowing:
:: Fourteen men were being held in custody in connection with the Manchester Arena attack.
:: Police remained at an address in Shoreham, one of the country's most expensive seaside towns.
:: Officers from Cheshire Police and Counter Terrorism Policing North West searched an address in Chester in connection with the attack.
:: GMP said they had also executed a search warrant in the Whalley Range area of south Manchester.
The Bank Holiday raids followed a flurry of police activity in Manchester over the weekend, with the arrest of a 25-year-old man in Old Trafford and a 19-year-old man in Gorton.
Police have been working round-the-clock since Salman Abedi killed 22 people, seven of them children, and injured more than 100 in the worst terrorist atrocity since the July 7 bombings in 2005.
A total of 16 arrests have been made in connection with the attack, although two people have since been released.
It has been reported that MI5 has launched two urgent inquiries into whether it missed the danger posed by Abedi, 22, amid allegations it was warned of his deadly intent.
The domestic security service is said to be investigating whether any glaring errors were made in the handling of intelligence before the attack last Monday night.
Spy chiefs are believed to have held an emergency review in the days after the atrocity, while a separate in-depth inquiry is being conducted to look at the decision making surrounding his case before the massacre, the Guardian reports.
A senior Whitehall source previously has said Abedi was a "former subject of interest" to the security services whose risk "remained subject to review".
On Sunday Home Secretary Amber Rudd said she would "not rush to conclusions" that agents, "somehow missed something".
In the wake of the attack it emerged British counter-terror authorities were grappling with 500 investigations into 3,000 individuals.
Security sources later confirmed to the Press Association that a further 20,000 individuals were said to have been considered ''subjects of interest'' in the past, meaning as many as 23,000 people have appeared on the radar of counter-terror agencies, although the period the figures cover is unclear.
Ms Rudd said MI5 was right to review the way it had dealt with Abedi in the past.
"I think it is the right first step.
"There is a lot of information coming out at the moment about what happened, how this occurred, what people might or might not have known," she told Sky News.
"It is right that MI5 take a look to find out what the facts are.
"We shouldn't rush to a make any conclusions at this stage.
"The important thing at this moment, I believe, is to allow the operation to continue and to conclude."
Ms Rudd was also questioned after it emerged that just one suspected jihadi has been banned from returning to the UK since temporary exclusion orders (TEOs) were introduced two years ago.
She said: "That doesn't mean they're not of value to intelligence services and police," she told the BBC's Today programme.
"They're a tool which the law enforcement wanted. We gave them that tool.
"They've just started to use them. They found a case where it was necessary.
"The numbers may be small, but it only take one to do the sort of damage we saw last week."
The suspect held in Shoreham was arrested after police entered a flat above a parade of shops in Brunswick Road in the town centre.
Local councillor Kevin Boram said: "I'm a bit shocked that we've been associated with Manchester.
"It's a great shame for our community."
It is not the first time the area has been linked to terror.
The Deghayes family, of Saltdean, have lost three sons killed fighting in Syria, while a fourth son has also travelled to the country to fight the Assad regime.
Relation Omar Deghayes was held by the United States as an enemy combatant at Guantanamo Bay detention camp between 2002 and 2007 after he was arrested in Pakistan.
In Manchester police raided the home of another Libyan family in the Whalley Range area of south Manchester this morning, with searches of the property continuing.
Some local Libyans said they were now scared about attacks on Muslims and their community being targeted following the police raids.
A young woman, who would only give her first name, Kada, said of the family raided today: "I cannot fault this family at all. Very friendly. We have lived here for six years.
"They have adorable children. Amazing family, very helpful.
"I feel bad for the families that aren't involved. I really hope we're not next.
"I have not left the house since the attack.
"I don't let my mum leave the house on her own now because my mum is an easy target and I'm worried."
GMP said later that another raid was under way, this time at a site in Bury.
The force tweeted: "Officers investigating the attack on the Manchester Arena are searching a site in Pilsworth, Bury. The search is currently on-going."
The investigation spread to an industrial site on the outskirts of Bury.
Greater Manchester Police said a search was on-going at premises in Pilsworth.
Police activity centred around a tip beside the M66 motorway, between Bury and Heywood.
Police officers stood on guard at the entrance to the Viridor site and also at a public footpath around it.
One worker in a fluorescent orange coat could be seen beside a man in a white boiler suit inspecting waste close to a large digger which was sifting through material.
Footage of the landfill site showed what appeared to be forensics investigators in white boiler suits and blue helmets raking through the debris near a large red tent.
Viridor confirmed its Pilsworth site was being searched. The company is assisting police.