Turkey's parliament voted Wednesday to investigate whether security forces were behind a grenade attack in the largely Kurdish southeast, a bombing that sparked days of rioting and allegations that the state was carrying out summary executions.

The vote to set up the 12-member commission was overwhelming, and conducted by a show of hands.

"I think it would be beneficial if parliament investigates this incident so that no question mark is left on the issue," Interior Minister Abdulkadir Aksu said just before the vote at a special session of parliament called to discuss the Nov. 9 bombing. Both the ruling Justice and Development Party and the opposition support an investigation.

"Our citizens should maintain their calm and trust us," Aksu said. "Everything is being done to shed light on the incident in every aspect."

The commission is expected to travel to the area of the attack to interview witnesses, and can call on the courts to prosecute suspects. It lacks the power, however, to force people to testify.

The military is deeply revered in Turkey, and investigating possible links between security forces and extra-judicial killings could be explosive.

"Are we going to become a state ruled by laws, are we going to break some taboos, or are we going to remain the same? The public wants to know the answer," said Esat Canan, an opposition member of parliament from Hakkari, where the attack took place.

"This is Turkey's last chance toward becoming a state governed by the rule of law," he said.

In the attack, a hand grenade was hurled at a bookstore in the overwhelmingly Kurdish town of Semdinli, killing one person. The store was owned by Seferi Yilmaz, a former guerrilla with the Kurdistan Workers Party, or PKK, who was convicted and served 14 years in prison for participating in the group's first armed attack in August 1984.

Yilmaz and bystanders chased the suspected bomber, a PKK informant, to a car outside and captured the suspect and two paramilitary police standing next to the car.

In the car, which allegedly was owned by the paramilitary police, there were reportedly hand grenades similar to the one used in the attack.

Canan, who witnessed the opening of the trunk of the car, said that inside there were also guns, plans showing Yilmaz's shop and a list indicating which Kurdish clans were pro-state and which were not.

The possibility that the military was behind the attack has raised fears that security forces may have been trying to carry out summary executions, which were common in the early 1990s in the fight against Kurdish rebels.