What violence does Cathy witness at Wuthering Heights. What are the probabale underlying reasons for the attack. Who does Linton believe is to blame?

Cathy witnesses violence when Hindley physically abuses Heathcliff. This violence stems from Hindley's deep-seated resentment towards Heathcliff, stemming from his jealousy and sense of inferiority towards him. Linton blames Heathcliff for the attack, as he perceives Heathcliff as a threat to his own position and inheritance at Wuthering Heights.