A firearms officer has been arrested over the fatal shooting of a man.
Jermaine Baker, 28, was shot dead on 11 December during an alleged attempt to spring two convicts from a prison van in Wood Green in north London.
The Independent Police Complaints Commission (IPCC) told a meeting held to address community tensions that the officer was arrested on Thursday.
It has opened a homicide inquiry, and IPCC investigators were in Wood Green on Friday appealing for witnesses.
On Friday Mr Baker's family released a statement which said: "Those who knew and loved Jermaine will keep him in their hearts and minds as they remember him."
IPCC commissioner Cindy Butts said the officer had been interviewed under caution and evidence suggested Mr Baker was in a black Audi when he was shot.
"In that car was what appeared to be a non-police issue firearm," she said.
She told the meeting the IPCC was taking detailed statements from a number of significant witnesses but at this stage no relevant CCTV had been found.
Further forensic examinations were taking place on the firearm found in the car and the gun discharged by the police officer, she added.
The Police Federation said it wanted to find out why the IPCC was "bandying words about" like homicide.
"I've never heard of that before," said spokesman Ken Marsh.
"It's a week before Christmas and this individual's [the officer] life has been thrown into disarray."
Haringey Borough Commander Victor Olisa said police did not believe Mr Baker was a gang member, as had been suggested in some newspapers.
Community spokesman Darren Henry said: "The police officers murdered Jermaine.
"He was asleep when he was shot. There are witnesses who are afraid to step forward because of the witness intimidation in the Mark Duggan case."
Ms Butts later said: "We do not know whether Jermaine was or was not asleep. This will clearly form part of our investigation."
Some in the audience raised the fact that after Mr Duggan's death there were promises body cameras would be worn by all police but it had yet to happen.
Mr Duggan, 29, was shot by armed police in Tottenham on 4 August 2011. The shooting sparked rioting across London and other parts of England.
An inquest in January 2014 found he had been lawfully killed.
At the scene: Beth Rose, BBC London
Passions were high at Tottenham Town Hall, where the main room was filled with 100 or more people.
There was anger whenever the shooting was described as a "death" with calls of "murderers" and "liars" echoing around the room.
Forced laughter was clearly audible when the police and IPCC said they "respected all lives".
The Reverend Nims Obunge of the Peace Alliance had to intervene to try to quell the, at times, hostile mood.
There were also stern words for the many journalists pressed against the back wall for the way some had described the area and its history and "made up" sources about gangs.
David Lammy, the Labour MP for Tottenham, told Radio 4's Today programme: "Jermaine Baker's life is no less than anybody else's who die in these circumstances.
"And if we live in a civilised country, you lose your life as a result of a police action, it should garner the greatest of scrutiny. That is the basis of having policing by consent in our country."
Mr Baker was fatally shot at 09:00 GMT on Friday 11 December close to the back of Wood Green Crown Court.
He died from a single gunshot wound, the IPCC said.
The shooting took place as Erwin Amoyaw-Gyamfi, 29, and Erun Izzet, 32, were due to be transported to the court for sentencing having pleaded guilty to a range of offences, including possession of a sub-machine gun.
The sentencing went ahead a short time later with both jailed for 14 years.
Earlier on Thursday, Met Commissioner Sir Bernard Hogan-Howe described the action by the IPCC to launch a homicide investigation as an "unusual turn of events".
He said: "The difficulty for me, and for us, is that we don't know what's led to their conclusion.
"If we got it wrong let's understand that, if we didn't let's understand that and deal with it quickly. I don't think it should linger on for the community's sake."
The Met said it had suspended the firearms officer while the investigation was conducted.
Following Thursday's meeting, Haringey Borough Commander, Ch Supt Victor Olisa, said: "We are all keen that they establish the full facts, as quickly as possible.
"I have reminded those attending the meeting tonight that this is why the IPCC will be diligently and independently examining the exact circumstances that led to Jermaine's death.
"It is only right and proper that any officer who has made the decision to use lethal force fully accounts for their actions.
"To this end it is only through a transparent and meticulous investigation that the best interests of justice and of all those affected can be served."