An interesting comment from a passenger on Amtrak's facebook page:
The gentleman was very bothered and offended, but he allowed search of his bags and room. My question is this: If he had refused to allow the Sparks Police Dept to search his belongings, could he have been escorted off the train? Keep in mind the search was being performed by the Sparks Police Dept - NOT Amtrak Police.While in walking to my sleeper car, I was approached by a man who said he needed to ask me some questions. I did not realize that the local "Sparks Police Department Officers" had boarded the train, or even if this type of action would happen and thought it was just another passenger. He proceeded to ask me about my trip, which I then asked for identification...