in programs like Crimewatch (UK) they always have a recreation of the crime if theres no CCTV footage.
so...
when doing any serious crime make sure that some of your team pretend to be a cameraman and sound man with all the equipment pretending to be makeing a recreation.
this way any witnessess wouldn't know if they had seen the actual crime or the recreation being filmed :-D
which would then mean when they made the actual recreation they'd have to have a filmcrew, filming the filmcrew filming the crime.
witnessess wouldn't know what the **** was going on :-D