Stating that you remember nothing, declining to cooperate or stating that you offer no comment should be the standard continual response to any prosecuting or investigating authority: whether that is the Police, I.Revenue, Councils, RSPCA, CAA or any other such officialdom.
All these authorities are interested in is quick cheap easy "wins".
They love people who "cooperate" who think that by doing the "right thing" they will be exonerated as the truth will out.
Sadly the individuals forget that what you get in court is 'law' and not 'justice' and they will be stitched up proper like a kipper.
Once they get the message that you are going to make it as difficult as possible for them, divert their resources, be as obstructive as possible and generally cost them hundreds of thousands in terms of time, resources and pure money......they will get the message.
The case will be dropped though "lack of evidence" or that classic catch-all used for sweeping things under the carpet that prosecution "would not be in the public interest".