Injuries or fatalities of suspects during police chases are not unheard of, and I am not aware of any other attempts at cover ups, or outrage by local members of the public. It feels almost certain that something dodgy or otherwise a major operational fuckup
Such e-bikes do 25 mph tops, and whereas it is of course possible to die from a crash at that speed, it is a low probability event, and far less for two people. If I had to speculate, my money would be on the coppers abandoning any duty of care towards the safety of those kids and knocking them off their bike, causing them to crash against a brick wall or another police car blocking the street. Or worse still, they were hit at speed by another cop car trying block their escape route, or the chasing van accidentally run them over.