Memorial services in the US and the UK will mark the 25th anniversary of the Lockerbie bombing on Saturday.
A church service will also be held in the southern Scotland town which was devastated when Pan Am flight 103 was blown from the skies on December 21, 1988.
The bombing of the flight from London to New York City killed 259 on board and 11 people on the ground in Lockerbie.
According to reports, an explosive device was placed in a Samsonite Silhouette 4000 suitcase and was smuggled unaccompanied aboard Air Malta Flight KM180.
The airport scanner did not detect the Semtex plastic explosive and the electronic clock timer allegedly inside a Toshiba BombBeat radio-cassette player.
According to the official version of the events, the aircraft took off in Malta and landed in Frankfurt. The luggage was then transferred to a flight bound for London, and again moved to Pan Am flight 103 headed to New York.
Operation Bird report
According to the Independent newspaper, the Operation Bird report concluded that the bomb departed from London, not Malta, and that Mohammed Abu Talb, an Egyptian with links to Palestinian armed groups, and not Libyan intelligence officer Abdel Basset al-Megrahi, was responsible for the attack.
The report said that Talb bribed a worker at Heathrow airport and smuggled the suitcase with the bomb inside onto the flight.
At 7:02pm, half-an-hour after takeoff from London, there was an explosion aboard Pan Am 103 while over the Scottish town of Lockerbie. According to investigations, the nose and cockpit separated from the fuselage and the plane rapidly disintegrated.
At 7:03pm the kerosene loaded wings and the the main cabin struck the town of Lockerbie. Several houses caught fire and 11 people died.
By 7:07pm all the wreckage had landed, scattering over an area of 1,360 square km.
Megrahi, who always denied involvement in the disaster, remains the only person convicted for the attack. He was jailed for life in 2001 but was released in 2009 on compassionate grounds following prostate cancer diagnosis.
According to Reuters news agency, he "arrived home to a hero's welcome. The next day, Britain condemned the celebrations in Tripoli.
"The release also provoked an outcry in the United States since most of the 270 people killed in the bombing were American."
Megrahi died in 2012.