This is the inquiry on the BBC World Service with me Tanya Beckett.

Each week one question, four expert witnesses and an answer.

A chartered flight travels from Syria to Iraq landing at Baghdad International Airport shortly after midnight.

A group of men walks across the tarmac towards two waiting SUVs.

Two climb into the first car, the rest of the group climbs into the second and the vehicles pull away.

At this same moment an MQ9 Reaper drone is cruising thousands of meters above them. It receives a signal to

release three missiles. The first two missiles hit the car traveling up front. The

third lands on the car at the rear. The impact instantly kills all of the occupants.

One of them is the Iraqi leader of the Iranian-backed Shia militia group Abu Madi al-Mohāhā But it's news of the killing of one of the other men in the same car that shocks the world.

His hand is identified at the scene, covered in ash and wearing

his signature Ruby ring. Kaseim Sulemani, Iran's top military commander and one of the most powerful men in the Middle East.

In this special episode of the inquiry, we've drawn together archive material and fresh

commentary to answer the question why was President Trump so keen to see

Sulemani dead and what will be the consequences of his assassination.

Part 1, the Dark Side.

I survived April 1983, the bombing of our embassy.

It was there for the bombing of the marine barracks,

244 dead Marines.

Ryan Crocker was made abundantly aware of Iran's long shadow across the Middle East during his posting at the U.S. Embassy in Beirut.

In 1983, in the space of six months the Americans were targeted by two bombings in the

Lebanese capital. Over 500 people died.

A pro-Iranian group calling itself the Islamic died.

...