Emergency services and police at the scene of the attack.
Most pit bull-type dogs descend from the British Bull and terrier.
“To attack the headquarters of Spain’s Socialist Party is to attack democracy.”
The suspects were caught on CCTV.
The victim, a local foreign resident, was left badly hurt on the ground.
The attack took place on Saturday.
Incident took place in the early hours of Tuesday morning.
The injured man remained unconscious on the ground until an ambulance arrived.
The rock which was apparently thrown at the British couple.
"I felt a large whack on the side of my head, my arm and leg stung moments afterwards."
Local Police were quickly on the scene.