Cardiff riot: Police avoid questions after statement
Reporters confronted police at the end of a press conference about the fatal Cardiff crash and riot which followed in the Ely area.
Ch Supt Martyn Stone said South Wales Police has referred itself to the police watchdog.
He also said the force had received CCTV footage of a police vehicle following the bike which crashed shortly before 18:00 BST on Monday.
"This will assist us in piecing together the circumstances leading up the the collision," he said.
After his statement, the officer declined to answer questions.