From the above linked article,
"Billy Chastain, 30; Mark Chastain, 32; Mike Sparks, 32; and Alex Stevens, 29, met up Sunday evening. They left Billy’s house around 8 p.m. on bicycles “pulling trailers,” (Police Chief) Prentice said".
Trailers, plural.
Looking at a map, it seems that the ride to the salvage yard, via S Madison Ave., was 1.3 miles of flat paved streets. Map estimate 7 minute ride.
Thinking what the purpose of the trailers is, if they were taking something there, didn't at least one of them have a car to take something there? And why would all 4 need to go? If no car is available, why do bikes at night? Why do 4 need to go and all met up at Billy's house first? Therefore the trailers are for something, and after dark for concealment. Maybe the auto salvage place removed the CATs, so thinking of other auto parts, they could have been working on cars at their houses. Just remembered, my brothers called this shopping at "Midnight AutoSupply".
If they're getting something to sell, head and tail light assemblies are good. Maybe they needed seats. Maybe this wasn't the first trip.
You don't need a lot of tools to remove these and even silent hand tools, drivers, sockets, etc will do.