The family of the Finsbury Park terror attack suspect have described the incident in north London as "sheer madness" and said they are "devastated for the families".
One elderly man, who had collapsed moments before the van appeared, was pronounced dead at the scene, although police have not yet confirmed whether he died as a result of the attack.
After Monday's attack, the alleged assailant was arrested on suspicion of attempted murder and later charged with the commission, preparation or instigation of terrorism, including murder and attempted murder.
It is the fourth terror attack in the United Kingdom in recent months, and the third to hit London, following a vehicle being rammed into pedestrians on the bridge next to the Houses of Parliament, the concert bombing in Manchester, and the attack on London Bridge and Exmouth Market in which two Australians were among those who lost their lives and in which terrorists also used a van to mow innocent people down.
Police said the attack, which injured 11, was clearly targeted at Muslims and Prime Minister Theresa May described it as a "sickening" terrorist attack.
The driver, who was seized by worshippers immediately after the attack, has been held by police for preparing or instigating terrorism.
One man also died after slipping outside the Muslim Welfare House as evening prayers concluded for the holy month of Ramadan.
The driver of the van has reportedly been arrested.
The Labour leader and local MP for Islington North spoke from the steps of north London's Finsbury Park Mosque.
Asked by ITV News what she thought when she found her son was in custody, she said: "Oh God... you just can't imagine".
In a statement, the family said: "We are massively shocked; it's unbelievable, it still hasn't really sunk in".
The witness now believes the sleeping man was Darren Osborne, and says he smelt of alcohol and was asleep with the van door open.
The incident is being investigated by counter-terror cops, who said they were not looking for any other suspects.
Pub regular Phil Henry said: "He was kicked out of here, the landlord said, for shouting about Islam. I know exactly what people are thinking by their looks", she said.
Other neighbours said that Osborne's behaviour had become erratic in recent weeks, and that he was living in a tent in the woods after splitting up with his long-term partner.
However, his neighbour, Khadijeh Sherizi, herself a Muslim, said he was "so normal" and "seemed polite and pleasant to me".
Faith leaders were joined by Metropolitan Police Commissioner Cressida Dick at the vigil, which started with a short silence.