Three protestors were attacked by supporters after they invaded the bullring in Albufeira on 9 August.
Clearly illustrative footage that did the rounds on social media showed the campaigners being beaten by spectators while already being restrained by GNR officers.
The video, posted by Peter Janssen of the Vegan Strike Group, has been viewed over 41,000 times, attracting scores of critical comments.
The activists were verbally and physically attacked after disrupting the bullfight in Albufeira, with the footage showing one of them being cursed and kicked by civilians as they were led out of the arena in handcuffs by police.
“In light of the extreme violence of some bullfight spectators upon demonstrators already immobilised by the GNR, the authorities showed signs of passivity and duality of criteria by not restraining the aggressors on the spot”, Francisco Guerreiro, a PAN spokesman, said in a statement.
“The party also questions how many people were injured in this event, how many similar incidents have occurred over the last 10 years in fixed and mobile squares, inside and outside the premises, what authorities were present at the scenes, how many operatives were called as reinforcement, and what formal identifications have been made”, the PAN statement fired off.
According to various media reports, the GNR has launched “a process of investigation” and the Department of Investigation and Criminal Action (DIAP) of Faro will also investigate the incident.
On 11 August , members of the Vegan Strike Group, which presents itself as an international organisation against animal abuse, also staged action at the Zoomarine sealife conservation theme park, jumping into the pools to draw attention to the captive lives of dolphins and other species found therein.
Another protest was held outside the bullring in Albufeira last Friday night, but this time the anti-bullfight campaigners withheld from invading the venue.