EXCLUSIVE: 'American mercenaries are torturing' Saudi elite rounded up by new crown prince - and billionaire Prince Alwaleed was hung upside down 'just to send a message'
Source in Saudi Arabia says American private security contractors are carrying out'interrogations' on princes and billionaires arrested in crackdown
Detained members of Saudi elite have been hung by their feet and beaten by interrogates, source says
Among those hung upside down are Prince Alwaleed bin Talal, an investor worth at least $7 billion who is being held at Riyadh's Ritz Carlton
Arrests were ordered three weeks ago by Crown Prince Mohammed bin Salman
Source claims mercenaries are from 'Blackwater', a claim also made by Lebanese president
But its successor firm denies it has any operations in Saudi Arabia whatsoever and says its staff abide by U.S. law
Americans who commit torture abroad can be jailed for up to 20 years