CNN  — 

Using new age-progression technology, FBI technicians created new photos of four alleged Pan Am Flight 73 hijackers. The release of these photos on Thursday signaled a renewed hunt to find and convict perpetrators of the 1986 hijacking in Karachi, Pakistan, an attack that left 20 people dead, including two Americans.

The bureau hopes the updated images – rendered using Adobe’s Photoshop program to show what the men might look like now – will generate new leads and encourage anyone with information to contact the FBI directly or submit a tip online.

“The FBI has worked tirelessly over the past 31 years to bring the perpetrators of the horrific 1986 hijacking aboard Pan Am flight 73 to justice,” said Andrew W. Vale, assistant director in charge of the FBI’s Washington, D.C. field office. “The use of aged-progressed photographs is just one investigative technique the FBI is utilizing to accomplish this mission.”

All four suspects have been on the FBI’s Most Wanted Terrorist List since 2009. Images of Wadoud Muhammad Hafiz al-Turki, Jamal Saeed Abdul Rahim, Muhammad Abdullah Khalil Hussain ar-Rahayyal and Muhammad Ahmed al-Munawar were originally obtained by the FBI in 2000.

The State Department’s Rewards for Justice Program is offering a reward of up to $5 million each for any information that proves useful in the arrests or convictions of the alleged hijackers. Officials stress that no matter how insignificant a tip may seem, it has the potential to bring the FBI one step closer to identifying the suspects’ whereabouts.

“We have a team of agents who are committed to furthering this investigation and locating these alleged terrorists,” Vale told CNN in an email.

It’s been more than 31 years since the deadly 16-hour tarmac standoff on September 5, 1986, when a band of terrorists led by Zaid Hassan Abd Latif Safarini seized control of Flight 73. The hijackers were eventually captured by Pakistan commandos.

Safarini, who confessed to the attack and pledged allegiance to the Abu Nidal Organization (ANO), was sentenced to 160 years in 2004. But the four wanted hijackers, last seen in Pakistan in 2008, remain at large.

“No matter how much time has passed or the obstacles we encounter,” said FBI special agent Terrence Mcintyre in a statement, “we owe it to the victims and their families to never give up on them.”