Towing Issues: damage during a tow, speed bump, accident investigators

Question
Lets start by saying that my car was towed by mistake. They tagged my car for no registration so the next day I got temporary tag and placed it in the window. Two days later I wake up and my car is gone! I see the tire tracks dragging the car from its parking spot directly over a speed bump there are fresh scrapes all across the speed bump and at the end of the tire tracks a piece of my bumper. I have taken pictures of the tire tracks the scrapes and the piece of my bumper at the end of those tire tracks. I showed the tow company my broken car explained my situation and they took me to the impound yard. the clerk saw my registration before I ever touched the car I placed the piece of my bumper in the spot where it was broken off and took more pictures of how it fit perfectly. They gave me my car back for free on the spot and then i followed the clerk back to the office and filed out a complaint. Now they have contacted me and said that it is impossible for damages to happen when using a flat bed. so after all that here is my question... is it possible that they drug my car? i drive a 2005 Volkswagon jetta GLI that is pretty low to the ground and wouldn't the speed bump be a cause for how it could have scraped? I live in Las Vegas and also wonder if you know of any tow accident investigators?

Answer
While I hate to get involved in fights over towing, you have started to do it all right...

The damage which you mentioned, does sound like it was dragged out of a space, and then loaded from the front since you have a front wheel drive vehicle..

But comments about using a flatbed, yes damages are harder to do with flatbeds, but they do cause them at times...  
How far is the speed bump from the parking space, as that is an issue worth looking at...  I can see dragging a car back a few feet, but a good distance (open to debate) is not good...  
One thing about flatbeds also is that it on the average takes about 50 feet of room for the flatbed to hook up and load the vehicle properly.

Bumper damage happens with flatbeds due to the angles of which the vehicle is loaded.  But towing them with a regular wheel lift tow truck from the rear also will cause the same angles which can cause damage..  

To me (my thoughts only) they used a wheel lift truck, hooked the back and pulled it out and then dropped it and rehooked from the front. As to tow accident investigators, not aware of any, but your auto insurance should have someone that can do the investigations...

You might not want to report it to the insurance for fears of rates going up, but they have trained people and bigger resources (IE  Lawyers) who can help get things resolved..