The Police Service of Northern Ireland has insisted it will prosecute anyone caught on film committing a crime.
In the latest outbreak of violence in north Belfast a number of nationalist protesters were photographed and filmed as they attacked police and British army vehicles. In many cases the attackers were not wearing masks.
A PSNI spokesman said the service would be looking through television evidence "slowly and with precision" and that if evidence could be gleaned from it it would be used in a prosecution.
Photographic evidence was less reliable as there was a difficulty in "proving somebody caught on camera was acting in commission of a criminal act", the spokesman said.