In Wuthering Heights:..........?

Near the end it Says there was an accident in March and that someone's gun burst while that person was out on the hills , a splinter cut his arm and he lost blood. I'm very keen in finding out who this person is...either Mr. Hareton or Mr. Heathcliff. In my book it's on page 398 out of 430 for those who want to do some research in case I haven't explained properly. I'm ust confused as it doesn't clarify who this person is. Please help!