Blood Simple movie question

Nothing earthshaking but I am curious…

In the movie what is the private investigator’s motivation for killing Abby and Ray? He seemed to take a lot of care in killing Abby’s husband in terms of planning but kind of went on a mini-rampage in the killing and attempted killing of the couple. And as far as I could tell they didn’t have anything on him - much less even know he existed.

I had to look at the IMDB plot summary; Visser (the PI) had reason to fear that Abby and Ray would turn over the doctored photo and Visser’s lighter to the police. He had left both at the bar.

As far as not knowing he existed – that’s kind of the dark joke of the movie, right? I think the most well-informed character is Marty, and he dies. Everybody else is confused about what everyone else knows or doesn’t know. (Or, if they’re Abby, they just don’t know anything.)

Realized later: Visser has figured pretty much everything out right as he’s dying at the end, I think – hence his laughter.

Ah, I forgot about the lighter. Still he could’ve just took it from them (at gunpoint). But I guess that wouldn’t have been a good movie.

Once Visser’s plan went awry, he panicked. I rather like how this movie shows normal-ish people flailing around as their worlds collapse …

(Remember, there was the safe, too — his failure to get into it would’ve heightened his paranoia. I didn’t get the impression he was a hit man; this might have been his first murder.)