My buddy has a potential "situation"

So my buddy came home one night around 2am and he sees a car a house or two down the street sitting there with his lights on. Old thunderbird. Well my buddy walks inside. He looks outside and the car creeps up and sits outside his front lawn as my buddy is looking outside his front door. The car leaves and later creeps by really slowly.

Next day he checks his mail and there is his normal mail and in the back of the box there is a package wrapped up in plastic. Like really shotty wrapping. He leaves it alone and checks it later. The package is gone.

A few days later the guy finds a black piece of construction paper rolled up on his front door. It has nothing in it except 5 black lines. Like this: l l l l l

We set out a game camera for him that is infrared. Hoping to catch a perpetrator. We think it might be a drug deal going on via his mail box but I can't explain the paper. What would the OB do? He's single and lives in LP