I'm part of a group at church which does jail outreach.
The drug epidemic across the country is bad, but until moving here a year ago I didn't have a clue as to how bad it is here. Four drugs are common here, meth, spice, heroin, and painkillers. Oxycodone appears to be real bad in the Midwest. People are suffering brain damage from meth and spice, I've come across inmates who take up to two weeks to get to some sense of normalcy after detoxing from meth and spice (synthetics). These folks get caught up in the system, and most can't get away from it. The jails are overflowing, here.
There could be a drug angle with the perp. It appears he might be smoking or vaping, vapes are used by addicts.
Now as far as hitchikers are concerned, MOO is RL probably did not pick up a hitchiker that day. One thing my friends and I do on a regular basis is borrow each others' vehicles. We just trust each other. I wonder if RL let someone borrow his truck recently, maybe someone on a short list of people of interest, someone who maybe has helped him on his property before.