Members of the network smuggled in excess of £42 million in cash out of the UK, making hundreds of trips to Dubai, UAE, between 2017 and 2019.
NCA investigators believe the money was profit from the sale of class A drugs and organised immigration crime.
Around £1.5 million was seized from couriers leaving the UK but flight analysis, evidence from cash declarations in Dubai, and other material seized by the NCA showed the group had succeeded in transporting far more.
As part of the investigation NCA officers also uncovered a plot involving members of the OCG to smuggle 17 migrants, including five children and a pregnant woman, into the UK in the back of a van carrying tyres in 2019.
The van was intercepted by Dutch police, who were working with the NCA, before it could reach a ferry at the Hook of Holland.
In November 2019, following weeks of surveillance, communications and flight data analysis, officers moved in to make arrests. Gang ringleader Charan Singh, 44, from Hounslow, was among those detained in a series of early morning raids across west London.
Investigators were able to prove that Singh, who was formerly resident in the UAE, paid for flights to Dubai for other members of the network so they could carry cash.
He also kept a ledger showing how much had been transported and when. It showed that at least 58 trips to Dubai were made by Singh and his couriers during 2017 alone.
Further arrests followed and those charged were prosecuted in two trials at Croydon Crown Court, starting in January 2023.
The first trial saw six people, including Singh, found guilty of money laundering offences. Two defendants were additionally convicted for facilitating illegal immigration along with a third individual.
Midway through the second trial six defendants changed their plea to guilty in relation to money laundering offences.
As a result, reporting restrictions on the case were lifted on Friday 5 May.
All 16 convicted are due to be sentenced in a hearing starting 11 September 2023, including two individuals who entered guilty pleas for money laundering offences prior to the two trials.
