BAHAWALPUR, Pakistan (DAWN/ASIA NEWS NETWORK) - Four suspects, including a woman, were arrested by the Pakistani police from Punjab state in connection with Tuesday's terror attack on a Peshawar army school that killed 140 people, majority of them school children.

The four were tracked through a mobile sim card which was allegedly being used by militants during the attack on Army Public School.

The sim was registered in the name of the woman who was taken into custody along with three others. A local mobile franchise dealer was also included in the scope of investigations.

On Thursday, Inspector General of Police Khyber Pakhtunkhwa region Nasir Durrani had said that a team constituted to investigate the attack was currently working on the available evidence. Mr Durrani had also said that leads coming from initial investigation of the school massacre extended beyond the country's borders.

Senior military officials had said that militants involved in the attack had been in direct communication with their handler in Afghanistan, one Umar Naray, alias Umar Khalifa Adinzai - a well-known commander of the Pakistani Taleban's Tariq Geedar group. "He was directing the suicide bombers and the attack group," the official had said.

More details on the arrests are awaited.