Nine people, including three 15-year-olds, have been arrested over the riot in Cardiff that was sparked by the deaths of two teenagers after they were followed by a police van.
South Wales police, which is being investigated by the police watchdog in connection with the tragedy, said there would be more arrests.
The details emerged as the Guardian obtained more footage appearing to show the van that had followed Kyrees Sullivan, 16, and Harvey Evans, 15, just before the e-bike they were riding crashed on Monday evening.
It seems to show the van heading down a street in the suburb of Ely after it had lost the boys. The van is still moving at some speed and hits a traffic-calming bump hard. Family members claim it suggests the van was still intent on catching up with the teenagers.
Five people were arrested on Thursday morning – four boys and men aged 16, 17, 18 and 29 – in the Ely area. A 21-year-old man was arrested in Tremorfa on the other side of the city. They were all taken into custody on suspicion of riot.
The police said four arrests were made on the night of the disorder – a 15- and 16-year-old from Ely along with a 15-year-old boy from Llanrumney and a 15-year-old girl from Roath, both several miles from Ely. The teenagers are all on police bail pending further inquiries.
As part of the investigation, more than 180 pieces of body-worn footage from police officers at the scene has been recovered and officers are going through hundreds of hours of CCTV and videos posted on social media.
Meanwhile, investigators from the Independent Office for Police Conduct (IOPC) have been on the streets of Ely interviewing witnesses and tracking down footage.
Initially the police and crime commissioner for south Wales, Alun Michael, said the riot had been sparked by false reports of a police chase before the boys were killed.
It was only after the Guardian and other media organisations found CCTV footage showing the boys being followed that the police admitted this had happened but have still refused to apologise.
The new footage shows a police van on Howell Road. It is believed the van that was following the boys turned on to this street as the teenagers rode up Stanway Road because the officers knew they could not get through the bollards at the end of that road.
South Wales police have said the van that had followed the friends was the first to get to the scene after the crash on Snowden Road but said no police vehicles were on that street when the boys came off the bike.
The timestamp on the new footage does not tally exactly with the known timeline but this is believed to be because the timer on the CCTV camera was slightly out.
Kevin Brennan, the Labour MP for Cardiff West, raised the issue of the regulation of electric bikes and scooters in the Commons.
Brennan said: “Can we have a debate on community safety, including the regulation of e-bikes and scooters?”
The type of electric bike Harvey and Kyrees were riding is able to reach a top speed of 45mph but they can be modified to go faster.
Wales’s first minister, Mark Drakeford, is expected to convene a meeting of community leaders on Friday to discuss the events of this week and the wider issues.
A statement released by Harvey’s school, Bryn y Deryn, described him as “a popular member of our school community”.
They said: “He always arrived with a big smile on his face and wisdom to share. He was an excellent sportsman and loved to debate on matters that he was passionate about.”
Greenhill school, where Kyrees was a pupil, said he would be remembered for his “quick wit and ability to make those around him smile”.
A vigil and balloon release has been planned for Friday at 6pm to pay tribute to the boys.
In a Facebook post, a friend of the families said: “We know tensions are still high right now. But we ask if tomorrow night for the balloon release people can keep their anger inside.” The friend said the mothers had also asked for no electric bikes to be seen as a mark of respect.
Deborah Coles, the director of Inquest, a charity that provides expertise on state-related deaths, said: “Two children are dead, their families are grieving, and the community has legitimate concern.
“Lies and misinformation in the early stages after a police-related death are all too common. These are tactics which are designed to deflect and distract from rightful public and community disquiet.”