Four people have been arrested on suspicion of conspiracy to defraud, conspiracy to launder money and possession of an explosive.
The two men and two women were detained as part of an investigation led by the Metropolitan Police's new Cyber Crime Unit.
The men are currently in custody at a central-London police station and the women have been bailed to return on a date early next year.
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Travel industry chiefs have called for universal safety standards to be introduced across Europe, to help prevent future tragedies.
The tragic deaths of two children on a Thomas Cook Corfu holiday in 2006 could lead to a crisis of confidence for the travel industry.
Sunny spells for tomorrow, although the further we go into the weekend then we will see outbreaks of rain moving south eastwards