How do I catch a newspaper thief? | Ask MetaFilter: "As a general rule, as long as the paper isn't delivered too early, you can ask you newspaper delivery to give a quick knock or ring your doorbell when they do the delivery, so you can make sure to grab it right away. (This works better if you've already tipped them well during the holidays.)

If you want to discourage the behavior without having to pounce on it every morning, the tried-and-true solution is to wait for the paper to be delivered, slip in a note to the effect of 'I know who you are', leave it back out in the corridor and hope that works.

Depending on the brazenness of the thief, though, that may not really work. I had a good friend whose family lived on the same block in DC as Felix Bloch, who was arrested for espionage. For an entire summer, while they were making a show of keeping him under surveillance, the street was lined with Secret Service cars--all US-make sedans, with two guys in the front seat, wearing shades and engines idling for the AC all day long. The big problem for the residents was that every morning, the agents would just get out of their cars and take the sports sections out of every paper on the block. I stayed with them for a week while this was happening, and every morning you'd walk down the street, and there are 12 cars, with the guys just sitting there reading your sports sections. What're you going to do--call out a Secret Service agent for stealing part of your paper?"