For many the sudden death of the government scientist and weapons inspector, Dr David Kelly, remains suspicious. The official verdict was suicide, but a public inquest was never held. The Conspiracy Files investigates the suspicions that still surround Dr Kelly's death in July 2003, when the controversy about Iraq's weapons of mass destruction was at its height. Doctors, lawyers, bloggers and politicians question the official account.

An investigation into the death of Princess Diana.

Oklahoma Bomb. An investigation whether the Oklahoma City bombing was the work of lone bomber Tim McVeigh, a decorated Gulf War veteran, or whether there were others involved who are being protected in a government cover-up. The programme features conspiracy theorists who claim that the US government not only had foreknowledge of the attack, they had informants inside the conspiracy who actively encouraged the bombing.

The 47-story tower collapsed seven hours after the Twin Towers and it has become the subject of heated speculation and a host of conspiracy theories which suggest it was brought down by a controlled demolition.

Nearly seven years on, the final official report on the World Trade Center is due to be published in July.

Official investigators are expected to conclude that fire caused the collapse of this third tower at the World Trade Center. But that makes this the first and only skyscraper in the world to collapse solely due to fire.

The Conspiracy Files explores many unanswered questions to try to find out what really happened, and why some people think there was a sinister plot to destroy the building.

9/11. An investigation of the growing number of conspiracy theories surrounding the 9/11 terrorist attacks on the United States of America in 2001. Some people believe that the American Government allowed or actively helped the attacks on the World Trade Centre and the Pentagon. And why was America so unprepared when terror attack warnings had been received? The Conspiracy Files travels across the United States to investigate and speak to eyewitnesses, and tries to separate fact from fiction.

Nearly four years after the 7/7 bombing, England's worst terrorist atrocity, The Conspiracy Files investigates the conspiracy theories flourishing on the internet.

There have been three official reports into the bombings on 7th July, which claimed the lives of 52 people along with the four people identified as the bombers, and injured 784 others.

The programme sees how conspiracy theories suggest four British Muslims were framed by the government, play on the fears of the Muslim community and spread a highly divisive and damaging message.

The Conspiracy Files: 7/7 examines the evidence in an attempt to separate fact from fiction. (BBC)

Examines what has happened to the world's most wanted man, Osama Bin Laden. Despite one of the biggest manhunts in history, Osama Bin Laden remains as elusive as ever. Rooted in the facts around Bin Laden's disappearance and the continuing threat of Al Qaeda, The Conspiracy Files looks at the claims that the video messages of Bin Laden are being faked and that he is really dead.

In December 1988, Britain's worst terrorist attack left 270 people dead.

After a massive police and FBI investigation, a Libyan intelligence officer was found guilty of mass murder, but he has now been granted a second appeal against his conviction.

Twenty years on, will the full story of Pan Am flight 103 finally emerge?

The Conspiracy Files follows the trail of evidence from the Middle East, through Europe and on to North America, investigating the tangled web of claims and counter-claims surrounding the Lockerbie bombing.