Riots broke out in Cardiff overnight with missiles thrown at police officers and cars torched after a fatal crash involving two teenagers.
Tensions reached breaking point after officers were called to the collision, in Snowden Road, Ely, at about 6pm on Monday 22 May.
Two teenage boys named locally as Kyrees Sullivan, 16, and 15-year-old Harvey Evans tragically died in the collision, with rumours circulating they were being chased by police before the crash, the Police and Crime Commissioner for South Wales has said.
CCTV video appearing to show a police van following two people on either a moped or electric bike has emerged - with a force spokesman saying it is now investigating.
South Wales Police have not confirmed how many arrests have been made but said several have taken place.
Trouble flared for hours in the community, with clashes between officers and gangs of youths.
Here's what we know so far:
Police were called to a crash
Officers from South Wales Police were called to a serious road traffic collision on Snowden Road shortly after 6pm on Monday.
The crash resulted in the deaths of two teenage boys.
Police responded to the collision which had already occurred when officers arrived, and they remained on scene to manage a large-scale disorder until the early hours of Tuesday morning.
Rumours circulated about a police crash
Police and Crime Commissioner of South Wales Police Alun Michael told the BBC that rumours of a police chase sparked the riots in the Cardiff community.
He said: “It would appear that there were rumours, and those rumours became rife, of a police chase, which wasn’t the case and I think it illustrates the speed with which rumours can run around with the activity that goes on social media nowadays, and that events can get out of hand.”
CCTV footage appearing to show police following bike before crash
The BBC uncovered CCTV footage which appears to show a police van following two people on an electric bike minutes before a fatal crash that sparked a riot in Cardiff.
The video was time-stamped at 5.59pm on Monday on Frank Road according to BBC Verfiy.
Frank Road is just over half a mile from the site of the suspected crash.
CCTV appearing to show a police van following a bike ahead of a fatal collision
Police cars torched and missiles thrown
Specially-trained public order officers were deployed to the scene, including officers from neighbouring police forces, as several vehicles were set alight, property was damaged and officers were injured.
Scenes being livestreamed on YouTube showed young people throwing fireworks and other missiles at a line of police officers with riot shields.
Shortly before midnight a car was set on fire and burned fiercely, while a second vehicle was overturned and also torched.
One person was attacked because rioters thought they were an undercover officer, according to a senior officer at the scene.
Police officers injured and arrests made
"Around a dozen" officers were injured in the violence following the collision, said Mr Michael.
Asked about objects and missiles being thrown at police, he said: “My understanding is that those things were thrown at the police and about a dozen officers were injured.
“None of them life-threatening, fortunately, but of course, there’s a lot a lot of luck involved in that."
Assistant Chief Constable Mark Travis added that "arrests have already been made" in connection with the disorder, and more will follow.
"We shall be maintaining an enhanced police presence throughout the week and into the weekend," he said.
“We would like to thank the public for their support and appeal to anyone with information or video footage to come forward and provide that to us.”
Police condemn violence towards officers and emergency services
Mr Travis said that first and foremost, their thoughts are with the families of the two boys who died in the collision and with those affected by the disorder which followed.
“These are scenes we do not expect to see in our communities, particularly a close-knit community such as Ely," he said.
"We received a large number of calls from residents who were understandably frightened by the actions of this large group who were intent on causing crime and disorder.
“The level of violence towards emergency services and the damage to property and vehicles was totally unacceptable.
“Our focus now is to fully investigate the circumstances of the collision and the appalling scenes that followed."
Pictures show the aftermath of the riots
'No excuse' for disorder
Welsh Conservative leader Andrew RT Davies said there is “no excuse” for the disorder that unfolded in Cardiff.
“It is deeply concerning to read the news this morning about the riots in Cardiff last night,” he said.
“There is simply no excuse for this kind of disorder in our communities and it is unacceptable that people have been made to feel unsafe in their own homes.
“My deepest condolences go out to the families of the two boys who lost their lives last night. My thoughts are also with the injured police officers, and I wish them a speedy recovery.
“I have submitted an emergency question in the Senedd today, to seek answers from the Welsh Government on what discussions they are having with South Wales Police regarding this concerning situation.”
Police issue update to public
South Wales Police provided an update to the press and public at around 5pm on Tuesday 23 May.
Ch Supt Martyn Stone says police are continuing to investigate the crash and disorder in Ely.
He says officers received reports of a crash just after 6pm yesterday and an electric bike was seized from the scene.
He added police are looking into footage and families are being kept up to date.
Mr Stone said: "We've received CCTV footage that shows a police vehicle following a bike, at just prior to 6pm.
"This footage is being recovered as part of the investigation and will assist us in piecing together the circumstances."
He added that when the collision occurred "there were no police vehicles on Snowden Road".
Officers performed CPR, he said, and at this stage, Mr Stone does not believe any other vehicles were involved.
Police are also appealing to witnesses to come forward.
During the riots, 15 officers have been injured and 11 went to hospital for treatment.
Mr Stone added that he acknowledges the impact of last night's events on local residents "who were understandably very frightened".
He adds the police are doing their best to find those responsible, saying: "A number of arrests have already been made, and more will follow."
Anyone with information about the collision or the disorder which followed is asked to contact South Wales Police quoting 2300166555.
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