Farooq Bhoja, the owner of Bhoja Air whose Boeing 737-200 plane crashed at 6.30 pm on Friday evening just before it was to land at the international airport in Islamabad, has been taken into "protective custody". He has also been barred from leaving the country, with authorities including his name on the "Exit Control List".
After visiting the state-run PIMS hospital in Islamabad where badly mutilated bodies of the victims, including women and children, had been shifted, Gilani told reporters that he had directed the interior minister to form a judicial commission to probe the crash which he described as a big tragedy.
Without investigation we cannot reach any conclusion, he said.
Gilani said many of the bodies have been handed over to their relatives after identification while the remaining will be given after the DNA tests which may take some time.
His comments came as Pakistani investigators launched probe against Farooq Bhoja, whose airliner's flight B4-213 from Karachi to Islamabad lost contact with air traffic control last evening as it was coming in to land at the Benazir Bhutto International Airport which serves both Islamabad and Rawalpindi.
The plane slammed into the ground at Hussainabad village, located less than 10 km from the airport, amidst bad weather.
Debris was scattered over an area of more than one kilometre and parts of the aircraft fell on some houses in the village though there were no casualties on the ground.
On the probe, interior minister Rehman Malik said the Federal Investigation Agency was directed to launch an investigation against Farooq Bhoja, a member of the family that owns Bhoja Air.
Bhoja was included on the interior ministry's Exit Control List, a document with names of people barred from travelling out of Pakistan, and he had been taken into "protective custody," Malik said.
An FIR had been registered and the investigation would determine whether the aircraft that crashed was "technically capable," he said.
The Director General of Civil Aviation (DGCA) had ascertained that the Bhoja Air aircraft had been tested and cleared by Pakistani authorities in South Africa, Malik said.
"What were the international standards followed during this testing? We will interrogate the team that tested the aircraft," he said.
The minister also noted that Prime Minister Gilani has ordered senior Pakistan Air Force officers to investigate the accident.
Bhoja Air was revived recently after being closed for over a decade due to financial problems. Media reports said the airline had a fleet of ageing aircraft, mostly Boeing 737-200s.
Following allegations about irregularities in the clearance of the airline, the DGCA had been asked to seal all its records, Malik said.
"We will investigate if there was any criminal intent and if this airline was deliberately cleared (despite lapses).
If this aircraft was over 20 years old, why was it bought as it may not have been equipped with facilities and modern gadgets," he said.
The airliner's black box had been found and would be sent abroad for decoding, Malik said.
All 121 passengers, including 11 children and infants, and six crew on the aircraft were killed instantly, officials said.
Mohammad Asif Majeed, Director of the Disaster Management Directorate, confirmed there were no survivors.
Islamabad and Rawalpindi had experienced bad weather, including rain and lightning, at the time of the accident, and several witnesses told TV news channels that they had seen the aircraft burst into flames after being hit by lightning shortly before it crashed.
However, there was no official confirmation of reports of a lightning strike.
Capt Arshad Mehmood, a Pakistan Navy pilot who lives near the site of the crash, told reporters that he had seen the aircraft stall and descend rapidly before it hit the ground.
He said he believed the pilot had "probably lost control" of the aircraft in "very rough weather."
This was the second major air disaster in the vicinity of the Pakistani capital since July 28, 2010, when an Air Blue airliner slammed into the Margalla Hills in cloudy weather, killing all 152 people on board.
The Civil Aviation Authority on Friday ordered an investigation to ascertain the cause of the crash.
Search teams that fanned out across the crash site faced problems in the initial stage due to rain and lack of electricity.
Authorities later sent generators and search lights to the site and investigators located the Bhoja Air airliner's "black box" or flight data recorder late in the night.