which is a mental illness wherin the stalker hangs a person's face on his delusional state and fantasy of a perfect romance. It can involve anyone from a casual date to someone at a McD's drive through to somebody on TV or in a movie or on a concert stage. It quickly deteriorates into vandalism and violence because the person being stalked has no access to the stalker's script and wouldn't follow it if s/he did. Stalkers also won't stop until they are stopped.
Stalkers are sick, something that has been seriously muddied by Hollywood's shitty romcom tropes. There is nothing remotely romantic about being stalked, it can ruin your life very quickly. Even when antistalking laws are in place, cops don't like to take it seriously because it has been portrayed as something romantic by Hollywood. It is not. It gets dangerous quickly. Whether this was stalking or a thrill killing, the cops most likely didn't take it seriously, "well, he didn't hurt you/steal your shit, nothing to see here get a dog/buy a gun." Stalkers need an involuntary commitment and treatment, chemically banishing the delusions so therapy has a chance.
This sounds more like a control trip/thrill killing/ attempt at the perfect crime, ice cold and calculated. Stalker killings are usually sloppy and poorly thought out. The stalker doesn't leave the scene in some cases, proud of his work and feeling justified.
Stalkers generally pick just one person at a time, not four of them, which is another way this doesn't fit the mold.
Either way, this guy is a sicko and needs to be medicated into the Thorazine shuffle for the rest of his life.
(I was stalked years ago and my case was cited when this state got its antistalking statute. I had to stop him by myself. He died a few years ago, I had nothing to do with it)