You watch. The phony bombs were created specifically to look like they were made by an idiot. The whole plot of addresses, misspellings, crudity, etc. but as they take these things apart they will discover they were assembled essentially in a Class 4 containment. No fiber, no dust, no hair, no DNA... then the investigators will realize whoever assembled them was one of them. Clearly someone who knew how to assemble an evidence free package was smarter than this idiotic plot. But no perps will ever be found because, frankly, as soon as they realize they are looking for one of their own they will quit looking.