A week on from the dramatic raid that captured Venezuela's Nicolás Maduro, details of the intelligence surrounding the operation are becoming clearer, but some mysteries still remain.
The mission took months of planning and intelligence gathering. In August the CIA is believed to have sent a team of undercover officers into Venezuela.
The US does not have a functioning embassy in the country, so the team could not use diplomatic cover and were working in what is known in the intelligence worlds as a "denied area". They were on the ground to scout targets and recruit people who could help.
US officials have said they had one particular source who was able to provide detailed intelligence on Maduro's whereabouts which would have been critical to the operation.
Identities of such sources are normally highly protected but it quickly emerged it was a "government" source who must have been particularly close to Maduro and in his inner circle in order to know where he was going to be, and when.
