Hi ya CREEPINGSKILLS....Just a theory (why not huh?) How about the towels being laid down on the floor and the perps walking out the door on the towels, not leaving any footprints, and picking them up behind them as they exited.]I've attached a picture of how it can be done.....it should help visualize what I mean.
https://modelemployi.files.wordpress.com/2015/06/dirty-towel.jpg
Edited to add: And, of course the perps would
want the towels to be black, so if they were stopped while driving back to Missouri, the blood would not be apparent on a routine traffic stop.
Now the purchase of "black towels" just might make sense....to make sure there were not "exiting footprints."