When I think about it, most psychotically violent people are probably locked up far, far before they are 39 years old like the age of the alleged truck driver. Like these people born with a propensity to violence are put into juvenile prison very early on, and then when they commit more acts of violence in those prisons, quickly the amount of time for their new offenses while inside prison, will add up to life in jail.
Every real murder I know of in real life comes down to 2 types. The first is to do with the drug war and enforcing monopoly territories and contracts. These killings involve killing other drug gang people, so are not frightening to the populace. As if you are not trying to forcibly seize drug territory to compete with them selling drugs, you are not in danger. By legalizing drugs this type of murder would go away, as the murders related to the alcohol gangs in the era of prohibition went away with the end of prohibition. (the alcohol 'gangs' became corporations and sought legal recourse when contracts were violated)
The second type of common murder is domestic violence related. 99% of the time involving alcohol and low IQ, emotional people going into a rage. Again, this type of murder is not scary to the general populace. If you don't want to die in a domestic dispute don't get involved romantically with someone in that class of people, you can tell who they are because the police are visiting their house every weekend to calm them down once they get drunk.
The point is the 2 types of actual murders are not very good at scaring the average person. The media rarely even covers these 2 types of murders, because it is so boring to the average citizenry. Enter the highly questionable murders, where a seemingly good citizen, suddenly turns into a homicidal maniac and threatens the very lives of anyone. (Allowing the tv viewers to feel fear and get their fear porn while watching the news). And also useful when it is budget time and the police forces are asking for a generous increase in funding, to be paid for by those good citizens.