Welcome to the inquiry on the BBC World Service. I'm Tanya Beckett. Each week at one question

for expert witnesses and an answer. On the morning of May the 10th, President Trump sent out a tweet which featured the

hashtag Obama gate. Later he was asked about it in a press briefing. This is what he said.

Obama game. It's been going on for a long time. It's been going on from before I even got

elected and it's a disgrace that it happened and if

you look at what's going on and if you look at now all of this information that's

being released and from what I understand that's only the beginning.

The tweet was passed on four million and from what I understand that's only the beginning.

The tweet was passed on four million times within a week.

But what was Trump referring to?

What is the crime exactly that you're accusing him of?

You know what the crime is.

The crime is very obvious to everybody.

All you have to do is read the newspapers except yours.

But is it obvious?

For Trump's supporters,

Obamagate is a reference to a broad allegation that at the end of his presidency

Barack Obama tried to damage his successor by spying on him and his aides.

Trump had said something similar before,

but this time the accusation came with more force and anger,

both of which could be attributed to one particular piece of news,

which was the revelation that a criminal case against a man called Michael Flynn might soon be dropped.

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