From the article:
Police say thieves often cannot resist tucking into a snack after breaking into a home, and traces of saliva on the food remains can yield a telltale signature of the criminal's DNA.
A handful of hungry crooks have been caught and jailed this way over the past decade, a phenomenon that has prompted curious scientists to wonder which foods may yield the best saliva sample.
The article cautioned that CHOCOLATE does NOT work well for this, because they eat it all and leave no good saliva samples behind. :-)