The Finsbury Park attack suspect may have originally intended to target a pro-Palestinian protest that saw thousands of people march through central London, it has emerged.
Witnesses who saw Darren Osborne drinking at a pub in Cardiff the night before he allegedly drove 160 miles in a hired van to launch the attack said they overheard him ranting about the Al Quds Day rally.
Led by the Islamic Human Rights Commission, the controversial march was set to start at 3pm on Sunday.
Drinkers in the Hollybush pub, in Pentwyn, said Osborne was thrown out the evening before after “ranting and raving” about Muslims and Sharia law, appearing to write notes as he drank alone in a corner.
The landlord, Andy Parker, described the 47-year-old as “very political with everyone he spoke to”.
"He was very motivated about the Muslim Al Quds Day rally going on on Sunday and London and kept saying: 'Our brothers and sisters are dying and someone needs to do something about it',” he told The Telegraph.
"He kept saying he would do something about it, but he kept going on about it, and was saying we need to 'stand up to Muslims' it is 'time we did something about them'.
"I did not like one bit of it so asked him to leave."
Another customer said Osborne repeatedly mentioned the rally by name, while claiming Muslims were “taking over”.
“Now I think about it maybe his plan was to target this march but then went to the mosque when that didn't work out,” he added.
Osborne’s family claimed he was “not a racist” in an initial statement but said he had been “troubled for a long time”, with his sister saying he underwent rehabilitation for drug and alcohol problems 20 years ago and had recently attempted suicide.
Osborne is believed to have returned to his white hire van after leaving the pub, being found asleep by a passer-by who called the police.
Edward Gardiner, a self-employed builder and plumber who lives near Osborne's home in Pentwyn, said: ”I called police because I saw a random van in my cul-de-sac with someone drunk in it and the door open," he said.
"I could smell alcohol on him and he was grunting and groaning. I poked him but he didn't respond so I called 101.”
South Wales Police confirmed officers were called to a van in the area shortly before 12.30am on Sunday
“Officers attended, a male was asleep inside the vehicle, which showed no signs of having been driven recently,” a spokesperson said.
“The officers’ assessment was that no offences were disclosed.”
The Metropolitan Police said the van used in the attack almost exactly 24 hours later had set off from Cardiff at 8.20am on Sunday and been driven to London.
At 12.21am on Monday, it hit a group of Muslims leaving night prayers in Finsbury Park, killing one man and injuring 11 more.
A man pronounced dead from multiple injuries at the scene has been named as 51-year-old grandfather, Makram Ali, whose family paid tribute to a “loving man who spent his whole life without any enemies”.
Relatives said Mr Ali had fallen to the ground because of a weak leg shortly before the attack but had recovered and sat up when the van struck.
Deputy Assistant Commissioner Neil Basu: “We are very grateful to everyone who has provided information so far – their accounts are assisting the investigation hugely - but we need more people to come forward and tell us what they saw and what they know about the driver of this van.”
The head of the firm that rented out the vehicle, Pontyclun Van Hire, called the terror attack “shocking and cowardly”.
Len Evans said: “Together with all the staff at Pontyclun Van Hire, I am doing everything I can to assist the Metropolitan Police in their inquiries.”
Detectives have released a photo of the van used in the attack, registration number PO54 CSF, while calling on anyone who spoke to the driver in the day leading up to the attack to call on 0800 789 321.
It struck near the Muslim Welfare House, whose imam Mohammed Mahmoud stepped in with other worshippers to protect the suspected van driver from an angry crowd of witnesses.
They flagged down a passing police van as the suspect was restrained on the ground, allowing officers to take him into custody.
Osborne, of Cardiff, has been arrested in connection with the incident and remains in custody on suspicion of the commission of terrorism, attempted murder and murder.
Four injured victims remain in hospital, including two who are in critical care.
Anyone with information that may assist the investigation is urged to either call police in confidence on 0800 789 321 or contact police online via a secure form at www.gov.uk/act
Anyone with images or footage relating to the incident is urged to upload them via the secure website here.