It was traced to the scumbag who got arrested, but as there was probably no proof as to exactly who was driving it at the time, its probably hard to pin anything on him. I reckon he just sat there for hours saying 'no comment'. They know how to play the game unfortunately.
I also suspect there's a lot of misinformation being fed to the police which pulls them in many different directions, the wider pikey community coming together to report conflicting sightings all over the place. All those leads need to be followed up on which takes time, and that's just what the arseholes want, as it gives them time to break it down and get rid of the easily identifiable bits.