Quote Originally Posted by Mista Sparkle
Some thoughts...

Go and speak to them. Act like you don't know that they are cops. Tell them you noticed that their car was there for a while and ask if they need any assistance. Dead battery? Need a jump? Need me to call a tow truck? Be a concerned neighborly person....

If they were watching you - you would probably never see them. They don't want to tip you off.

Or you could call the police and tell them that a shady looking vehicle is loitering in the area
Good idea, I agree with this. It is always better safe then sorry though, the hell you'd go through for getting caught greatly outweighs not being paranoid (as long as you arn't over paranoid and crazy like that guy who was here before and though his coworkers wanted him dead or something).