KARACHI, Dec 30: Investigations to find out the nature of the Saturday explosion taken place in an inter-city bus are still inconclusive as police and other agencies do not have a clear answer regarding what caused the massive blast, it emerged on Sunday.

A powerful explosion took place inside a bus near the Cantonment Railway Station on Saturday that killed at least six people and left at least 50 others, including women and children, injured.

Although the police refrained from calling the incident ‘an act of terrorism’, they were also unable to find credible signs to declare the blast an accident.

“Still there is no consensus over the nature of the blast that took place in the bus. The material collected from the crime scene will be send for a forensic examination tomorrow (Monday) and it will be clear once the report is issued,” said DIG-South Shahid Hayat.

“We are going to register an FIR under the Explosive Substance Act since people have been killed. However, if results come otherwise, the FIR can be cancelled later,” the DIG said.

Officials and witnesses said that the huge explosion ripped through the 70-seat bus just a few metres from the entrance to the station at around 3.15pm. The blast, which was heard miles away, left the bus (ND-2888) in a blaze, with its roof torn apart. It caused panic in the congested neighbourhood that houses a number of restaurants, eateries and low rent hotels and is not very far from the Army House.