A police officer driving a van that followed two teenage boys on an electric bike shortly before it was involved in a fatal crash, prompting a riot in Cardiff, is being criminally investigated for dangerous driving. The Independent Office for Police Conduct (IOPC) has been examining whether the marked van was chasing Kyrees Sullivan, 16, and Harvey Evans, 15, who were killed moments after CCTV footage caught the police vehicle just behind the bike. Both the driver and the passenger in the police van had previously been served with a gross misconduct notice, notifying them their conduct was under investigation. The IOPC said on Thursday: “The driver of the police van has now been informed they are being criminally investigated for dangerous driving … A decision over potential disciplinary proceedings and any referral to the Crown Prosecution Service, will be made at the end of the investigation. “It should be stressed that the serving of notices and the criminal letter do not necessarily mean that disciplinary or criminal proceedings will follow.” In the hours after the riot in the Ely area of Cardiff in May, the South Wales police and crime commissioner, Alun Michael, claimed the riot was provoked by false rumours of a police chase. It was only after the Guardian, other media organisations and family members of the boys tracked down CCTV footage showing the police van shortly before the crash that the force admitted its officers had been following them – but said the van was not in the road when the boys came off the bike. The emergence of the footage led to the IOPC beginning its investigation. The IOPC said: “Our independent investigation, which began three months ago, is looking at the nature of the police interaction with the boys before the collision and how appropriate the officers’ decisions and actions were. A key consideration is whether there was any point at which the officers’ decisions and actions in the police van constituted a pursuit. “We have completed all our inquiries in the area and obtained a number of statements from local residents. IOPC investigators continue to examine hundreds of video clips that we have gathered as a result of our house-to-house inquiries at properties in Ely. In addition to these lines of enquiry, we have reviewed body-worn video from officers who attended the scene and we have taken statements from relevant police officers and staff.” David Ford, the IOPC regional director, said: “Our thoughts and sympathies remain with the family and friends of Kyrees and Harvey and everyone impacted by the tragic loss of two young lives in Ely. “We would still encourage anyone who believes they have useful information to come forward to us. We are continuing to engage with local community leaders and elected officials to provide updates on our investigation. We remain committed to establishing the facts of what happened.”