Epstein claimed he was beat up (according to news reports). Even so, some speculated that the incident was actually a "failed hit".
I am questioning the latter speculation by pointing out the lack of evidence that "failed hits" that leave so little evidence are an actual thing that happens. Epstein was found on the floor of his cell with a bruise on his neck. That means whoever supposedly attacked Epstein wasn't interrupted mid-act, but rather had time to complete his "work" to his satisfaction and leave of his own volition. If all Epstein had at the end of it was a bruise, the most reasonable interpretation is that that's all the attacker intended. If the attacker had intended to kill Epstein, Epstein would have been dead.