A cop accused McDonald’s employees of taking a bite out of his sandwich. Turns out, he ‘forgot’ he ate it.

when looking for suspects it is best to start with the ones nearest at hand. in other words, the family. bring in the mother and father first. look at them severely and say "what have you done?" if they don't immediately break down and confess, then move on to the children. take each one into a bare room with cinder block walls and leave them there for several hours all alone. then offer them a plea bargain if they will rat out their parents. 
after this procedure is followed, do a lineup. get a dozen random people off the street, line them up against harsh lights on a runway, and award one of them a prize for best original shoe size. if they don't confess to anything they should be told to leave town within 48 hours.
if all else fails start dusting for fingerprints and have the forensic lab analyze dust, pollen, and especially dandruff flakes from the scene of the crime. run the results through the Etch-a-Sketch; if a match is found issue an APB as well as a UPS and also a BVD. when all is said and done the only way to trap and convict suspects is with old-fashioned pimento loaf -- and hold the mayo.