At least four suspects, including a woman, were arrested in Pakistan’s Bahawalpur district in connection with Tuesday’s attack at an army-run school in Peshawar that claimed the lives of more than 140 people, mostly children, reports said Friday. The woman was reportedly identified by her first name, Shazia, according to Pakistan Tribe, a local news outlet.

The suspects were reportedly tracked down using a Subscriber Identity Module (SIM) card allegedly used by the attackers and later recovered by police from the school. The SIM card was registered under the name of the woman, who was taken into custody from the Gharibabad area of Hasilpur, Bahawalpur district, about 480 miles south of Peshawar.

On Thursday, Nasir Durrani, a police official in the restive Khyber Pakhtunkhwa province in the country’s northwest, reportedly said that the team investigating the deadly attack is working on the available evidence, while crime scene investigation officers were helping to collect evidence from the scene.

He also revealed that the leads obtained from preliminary investigation of the school attack had been extending beyond the country’s borders, The Dawn reported.

Prime Minister Nawaz Sharif condemned the attack on the school and vowed to launch fresh investigation against terrorism in the country.

"Our aim is to clean this region of terrorism. Not only Pakistan and Afghanistan but indeed this entire region should be cleaned of terrorism," Sharif said at a press conference. "These sacrifices will not go waste and we all want complete elimination of terrorism from Pakistan."

In the wake of the recent Taliban attack, Sharif also lifted a ban on death penalty on terrorism-related cases in the country.