Kanwarpal Singh blamed Brar for linking the London attack to the raising of the memorial.
"He is trying to become a hero by raising the memorial issue," Kanwarpal Singh said.
Another radical leader, who sought to remain anonymous, said the attack could be a "staged drama".
While the Akali Dal, which indirectly controls the SGPC, had washed its hands off the memorial, saying it has nothing to do with it, its alliance partner Bharatiya Janata Party (BJP) had opposed the memorial.
"There are certain fringe elements still in Britain, Canada and the US who try to keep the Khalistan issue alive. The London attack could be linked to that. Punjab Police officers who are on the hit list, take precautions when travelling to these countries," a senior police officer told IANS.
Punjab government spokesperson Harcharan Bains told reporters here: "The incident happened in London. Punjab has nothing to do with it."
