The Chief Justice of Pakistan’s Supreme Court Iftikhar Mohammed Chaudhry  said on Wednesday that he would probe the bloody attack on ex-premier Benazir Bhutto’s homecoming, wading further into the country’s deepening political turmoil.

The suicide blast during Bhutto’s homecoming parade in Karachi on October 18 killed more than 140 people, the deadliest incident in a wave of violence that has raised fears for Pakistan’s stability.

The government has vowed to expose those responsible for an attack. However, Justice Chaudhry expressed impatience with an investigation that is under intense international scrutiny as Pakistan moves toward crucial elections.

The Supreme Court will review the bombing to ensure the “perpetrators of this barbaric act are brought to book, which will result in restoring the confidence of the nation in the system of governance,” a court statement said. It scheduled a hearing in the case for Thursday. The court said it was looking into the attack partly because of the damage to Pakistan’s image, business confidence and campaigning for January elections.

In remarks likely to irk authorities, it also noted that “more than a week has passed since these bloody explosions occurred, however, no clue has so far been found explaining the reasons and the persons involved.”

“This incident has not only shaken the confidence of the entire nation, but it has also negatively affected the business environment in the country and resulted in a very poor projection of Pakistan in the world community,” it added.

Bhutto’s party has called for foreign experts to assist the investigation — a demand rejected by the government, which insists it can solve the case on its own. Bhutto has accused hard-liners in the government and security forces of conspiring to kill her and criticised the police investigation into the October 18 attack.