The old cat was close to 20 years old and was in declining health and had become less and less able to get out of the way. The other three dogs were pretty respectful of the old cat. But the pit bull had, well, it had attitude issues.
I learned last night that the pit had accidentally bitten one of the other dogs a couple of days prior. The bite was bad enough to need some surgery and a drainage tube installed.

Oh yeah, side note, it probably didn't help that he hadn't been fixed and was swaggering around with a set of balls.
Anyway, the cat got its back broken and had to be taken to the vet to put him down and out of his misery. Already a really tough day. And then the mother next door made the decision that the pit had to go as well. Which, I think was the right thing to do.
But that doesn't make their hearts any lighter or their house any less emptier for the dual loss of both a long cherished cat and a dog that they had come to love but knew things were not going to improve and could get much, much worse.
I should also note now that the pit bull was not, as was first reported (and I posted here about) to me, responsible for the death of the other neighbor's chihuahua. The chi pup was accidentally stepped on by the largest of the four dogs next door and its back was accidentally broken. Which is a tragic accident for all concerned since the big black lab next door is just an over-sized sweetheart.
For my own part, I'm kind of relieved that this dangerous dog is no longer next door. That there will be no more battles through the fence with my dog. That I won't have to keep a close eye on my kids when we happened to be out front when the pit was around. I feel bad for my neighbors but I am happy that the maladjusted and unpleasant dog is no longer around.