What are my chances???

[ManDownUnder]

Tell 'em your interested in helping them and would like a photo to do so.

They supply you with what evidence they have, you look like the good guy, and if they have nothing to send you, (i.e. they can't help you) you simply say you can't help them.

Keep a copy of the letter on file too...
Good luck!

[marty]

ask for more information - time date place (although that should be on the letter already). photo/video capture if available. don't give any details about who may have been riding at this stage

[DevoDave]

The bad news is that unfortunately there is "Owner Onus" which, paraphrased, means that as the owner of a vehicle you are responsible for any offense commited using that vehicle and you are required to provide the name and address of any person using the vehicle at the time of the alleged offence.

The Almost good news is; The prosecutors have to prove that an offence occured and it hey have a photo then it is pretty well "good night nurse" but if they are reliant on information provided by a member of the public then you will have a good chance of defending any such charge as most of the great unwashed are not well versed in firstly observing an offense and secondly are pretty poor in giving evidence.

If it were me I would initially deny all knowledge of the said offence and request further information placing your bike at the scene and then if they are able to do that defend the charge and see what information they are able to produce in court, you are always able to change your plea if the evidence stacks up agains you.

If if is a civilian witness a good lawyer should be able to tear their evidence to shreads.

Good luck.