Maybe? One of the characters heavily abuses alcohol and we are told that this is the cause of his death however it is hinted that maybe he was killed by Heathcliff.
A character describes a plan he had to kill a man and then himself. He states he no longer wishes to do so, but may wish to again in the future. He references it again in chapter 11.
The relationship between Catherine and Heathcliff is borderline incestuous, as Heathcliff was adopted by Catherine's father and they were raised together as foster-siblings