A Bulgarian official has said those who attacked a man after he held a gas pistol to the leader of the opposition party may themselves be prosecuted.
Oktay Enimehmedov, 25, mounted the podium where Movement for Rights and Freedoms leader Ahmed Dogan was giving a speech, pointing a gun at his head.
The incident happened at the National Congress Centre in Sofia on Sunday.
Mr Enimehmedov was rapidly tackled by security guards who pinned him to the floor, where he was punched and kicked.
After the scuffle, he was arrested and taken to hospital. He had used a non-lethal weapon used largely for self-defence in the attack.
Deputy Prosecutor-General Borislav Sarafov told Bulgarian National Radio that his office was investigating who took part in the beating of the assailant after his gun was taken away.
Video of the incident has been widely circulated and social media users have expressed disgust at the way the attacker was treated.
Nedelcho Stoychev, director of the interior ministry's psychology institute, said that Mr Enimehmedov did not technically try to murder Mr Dogan.
"He primarily wanted to hurt him emotionally, not physically," he said, stressing that a potential shot from the gun would have caused, at worst, mild skin injuries.
He said Mr Enimehmedov had not told anyone about what he intended to do, apart from writing a note to his mother saying he was sorry he would not be completing his degree.
The 25-year-old, an ethnic Turk from the Black Sea town of Burgas, was reported to have had a criminal record for drugs possession, robberies and hooliganism.
Mr Dogan's liberal MRF party represents ethnic Turks and other Muslims, who make up about 12% of Bulgaria's population of about seven million.
Attacks on politicians are rare in Bulgaria, but in 1996, former Prime Minister Andrei Lukanov was found shot dead near his home in Sofia.