The US Federal Bureau of Investigation (FBI) has re-launched its search to catch four hijackers of the Pan Am Flight 73, almost 32 years after the failed attempt at Karachi airport.

“No matter how much time has passed or the obstacles we encounter, we owe it to the victims and their families to never give up on them,” Dawn on Friday quoted an FBI case agent as saying.

The attack, which occurred aboard Pan Am Flight 73 during an airport stopover in Karachi on September 5, 1986, resulted in the death of 20 passengers and crew. The victims included citizens of the US, India, Pakistan, Britain, Italy, Denmark, Ireland and Mexico.

The FBI has age-progressed photos of the four hijackers — Wadoud Muhammad Hafiz al-Turki, Jamal Saeed Abdul Rahim, Muhammad Abdullah Khalil Hussain ar-Rahayyal and Muhammad Ahmed al-Munawar — and released to the media to enable people identify them.

Since two Americans were also among those killed in the failed attempt, the FBI is legally bound to continue to seek the suspects until they are either brought to the US for trial or their death is confirmed.

The US State Department is also offering a $5 million reward for information leading to their arrest, through its Rewards for Justice Programme.

The four suspects are believed to have been members of the Abu Nidal Organisation, which was designated a terrorist organisation by the US Department of State. Each of the men is on the FBI’s Most Wanted Terrorists List. The case is being investigated by the agency’s Washington Field Office.

According to the FBI, Wadoud Muhammad Hafiz al-Turki was born on June 21, 1955 in Baghdad; Jamal Saeed Abdul Rahim on September 5, 1965 in Lebanon; Muhammad Abdullah Khalil Hussain ar-Rahayyal on November 27, 1965 in Lebanon; and Muhammad Ahmed al-Munawar on May 21, 1965 in Kuwait.

There were 365 and 16 crew members on the Boeing 747-121 when it arrived at the Karachi airport from Mumbai’s Sahar International Airport on September 5, 1986.

The Pan American World Airways Flight 73 was preparing to depart Jinnah International Airport for Frankfurt, and then to its final destination, John F. Kennedy International Airport, New York, when a group of five hijackers seized the plane.

The leader of the group Zayd Hassan Abd al-Latif Masud al-Safarini, also a Palestinian, was prominent member of the Abu Nidal group.

The 17-hour long hijacking came to an end when the hijackers opened fire on passengers, causing Pakistani commandos to raid the plane. They freed the aircraft and captured the hijackers.

At a trial held in 1988, all of the convicts admitted to having carried out the hijacking and were given death sentences that were later commuted to life imprisonment.

Safarini was released from prison in Pakistan in 2001 but was arrested a day later by FBI agents in Bangkok on his way to Jordan. In May 2004, a US federal judge in Washington sentenced him to 160 years at Super Max prison in Colorado.

Four other hijackers were released after completing their jail terms and deported to the Palestinian territories. In 2010, news reports claimed that Jamal Saeed Abdul Raheem was killed in a US drone strike on January 9, 2010 in North Waziristan.