Janet Elms' home in Carmarthenshire, west Wales, was searched by counter-terror police on Thursday as part of the "fast-paced investigation" into her son Masood who mowed down dozens of pedestrians on Westminster Bridge on Wednesday before fatally stabbing PC Keith Palmer in the grounds of Parliament.
Three of the pedestrians were killed by Masood, who also called himself Adrian Elms and whose birthname was Adrian Russell Ajao.
Following yesterday's search on Ms Elms' home, police have been seen guarding the farm where she lives with her husband, chickens and her border collie.
She runs a business selling hand-made bags and cushions on hand crafted gifts website Folksy.
On the site, she says: "Hello, I'm Janet and I live in rural west Wales with my husband, border collie and a few chickens.
"Our home is tucked away at the end of a little land, and it's here that you'll find me making bags and cushions.
"I use natural fabrics, both new and recycled, and love to make use of old Welsh wool blankets.
"All items are one-off. You may see the same style of bag, or the same fabric may reappear in a different guise, but never the same thing twice."
Mark Rowley said two more arrests were made
Ms Elms gave birth to Masood on as a 17-year-old single mother and within two years she married Phillip Ajao and lived in a £300,000 house in the coastal town of Rye, East Sussex.
Twenty years after that they moved to Tunbridge Wells with Masood's two half-brothers, Alex and Paul.
Neighbours of his mother said there was a heavy police presence in the village yesterday, which can now be revealed as a search on her home.
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Masood's mother's house in Carmarthenshire was being guarded by police today
One local, said: "We heard rumours early yesterday. Then police streamed up the drive to the house. I've heard what the connection is and I'm stunned."
Today police were seen entering 50-year-old Paul Ajao's home in Banbury, Oxfordshire.
Officers made two more "significant arrests" overnight in the West Midlands and the North West of England, Mark Rowley, the Met Police Assistant Commisioner, said during a briefing this morning.
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Ms Elms runs an online business selling homemade bags and cushions
The number of arrests has now risen to ten, with nine still in custody after a woman from Birmingham was released on bail.
He revealed two of the victims of Masood's attack on Wednesday afternoon remain in critical condition in hospital, with one in a life-threatening condition.
Yesterday terror group Islamic State (ISIS) claimed Masood was a "soldier of the caliphate" and praised him for carrying out the attack in which he stabbed PC Keith Palmer to death inside the grounds of Parliament and killed three others by running them down on Westminster Bridge.
Questions have now been raised as to how the 52-year-old, born in Dartford, Kent and raised in the picturesque seaside town of Rye in East Sussex, then Royal Tunbridge Wells in Kent, was radicalised – to such an extent he changed his name entirely and carried out an attack against Western civilisation.
Mr Rowley, said: "Clearly that’s a main line of our investigation. What led him to be radicalised? Was it through influences in our community, influences from overseas or influences from online propaganda?
"Our investigations, our arrests will help in that but the public appeal will make a big difference in that, if people come forward with more information.
"It would be wrong for me to say any more than what the Prime Minister said in Parliament yesterday.
"But, we’re looking at his history. Several years ago he had been a peripheral figure, he’s never been part of the mainstream intelligence picture about terrorism."
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4 dead and 40 injured in London terror attack
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Armoured police personnel carriers are seen on a street leading to the Houses of Parliament in central London on March 24, 2017 two days after the March 22 terror attack on the British parliament and Westminster Bridge
It is believed Masood may have been radicalised in jail, or in Saudi Arabia where he spent four years and converted to Islam.
After he returned to the UK he taught English at a centre in Luton, Bedfordshire, and in 2012 set up his own business in the West Midlands, it is claimed.
Floral tributes to PC Palmer and the other three victims have been placed outside Parliament
A vigil held at Trafalgar Square on Thursday night drew thousands of politicians and Londoners
The fourth victim was named as 75-year-old Leslie Rhodes, of Streatham, south London.
He died in hospital yesterday after his life support was pulled.
Mr Rowley said two police officers injured on Westminster Bridge as they walked back from a commendation ceremony remain in hospital with "significant injuries".
Giving further information on how the investigation was going, Mr Rowley said searches at five addresses are ongoing and 16 have finished.
Masood knocked down dozens of pedestrians on Westminster Bridge before getting to Parliament
He added detectives have seized 2,700 items from the searches, including "massive amounts of computer data".
Officers have spoken to about 3,500 witnesses, including 1,000 who were on Westminster Bridge and about 2,500 who were in Parliament.
Mr Rowley added any information from the public about Masood would be extremely helpful.
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He added: "We remain keen to hear from anyone who knew Khalid Masood well, understands who his associates were and can provide us with information about places he has recently visited.
"There might be people out there who did have concerns about Masood but did not feel comfortable for whatever reason in passing those concerns to us."