From the evidence, I conclude that this man was murdered.

She wore a gray tailor-made jacket over a white silk blouse that looked frilly and festive because of a kind of bow between the lapels, to one of which was pinned a bunchlet of violets.

As for the wonderful feats of horsemanship one hears of or sees among the Arabs, they are due to sharp spurs like razors, and to bits strong enough to break an animal's jaw. … Their favourite feat at their fantasias or fêtes of suddenly pulling up their horses short while at hand-gallop, ruins their legs, and there is in consequence scarcely a horse to be seen whose hind-legs are not spavined.

Given that all other current-day religions have turned into something unrecognizable in the Duneverse, it does seem a bit odd to have a Rabbi running around. But I haven't read the later Frank Herbert books, so it's possible he explained it there.