So, after Septimus Signus gets killed inside the Dwemer Cube by Hermaus Mora(? - can't remember for sure which Daedric prince), I went an looted his stuff. It still showed up as "stealing" his items, but I figured, eh, whatever. He's dead, he won't miss it.

Turns out he did. A while later in the game, a group of thugs showed up and attacked me out in the wilderness, and one was carrying a contract signed by Septimus Signus (who signs their actual name to such a document? lol)

So, I'm left wondering how someone who is dead could put out a contract on me for stealing, when I only stole his stuff after he was dead?

Well, he did gained knowledge from an Elder Scroll.

It was either next week's lottery numbers, or the name of the person who will kill him. Seeing as hired thugs can't exactly do much against a Daedric Prince, he chose the next best thing, kill the person who stole his sweetroll.

Same happened to me.

that's what you get for stealing his sweet roll, LOL