Who killed Sandor Clegane?

Who killed Sandor Clegane? Cersei calls Sandor a coward and a traitor for his abandonment of the Battle of the Blackwater. After learning of the incident at the tavern, Tywin raises the bounty on Clegane from ten to one hundred Silver Stags. Biter attacks Sandor, seconds before he kills him.

Cersei calls Sandor a coward and a traitor for his abandonment of the Battle of the Blackwater. After learning of the incident at the tavern, Tywin raises the bounty on Clegane from ten to one hundred Silver Stags. Biter attacks Sandor, seconds before he kills him.