I share a lot of your same thoughts and questions.
An area I'd like to elaborate on is the car, because it has been brought up in multiple posts. At first I also thought it was strange that LE didn't give specifics about its make, colour or model but after mulling it over for a while I'm thinking it was a calculated choice so they would avoid getting a barrage of useless tips. Lets say for example they cited it as a 'white truck', then they'd likely be getting tips about everyone in town who owns a white truck. I'm thinking it was probably the only vehicle parked in that lot on Feb 13th during the hours of 12-5pm (since the building was abandoned you wouldn't expect any vehicles in the lot, so it would stand out as suspicious). As a witness passing/driving by, you either saw a vehicle there or you didn't, it doesn't really matter the make, model, or colour. Also, LE specifically asks for information about the 'identity of the driver of the car parked....' not tips about the vehicle.