Where would Dorner get a SAM? It would be either stolen from the military or smuggled into the country.
Unless there is some idiotic DHS program to dole out SAMs to police departments.
The guy was a cop.
If he happened to pull over somebody with a broken taillight, he could easily noticed an RPG in the vehicle.
Take the RPG, issue a strong verbal warning, and let the driver go.
Nobody is the wiser.
Idiotic, but not to be confused with "out of the realm of possibility". Who would have seriously imagined the militarized thugmobiles that are out and about these days.
Remember when LAPD attacked the milk factory?
http://www.anyclip.com/movies/dragnet/friday-and-streebeck-attacking-the-milk-factory/
The same place he got his suitcase nuke!/sarc.