Terrorist certificate placed in envelope from Saudi embassy in Washington
Details sparked concerns government may have links to the terror attacks
Relations between US and Saudi are at a low point, with Obama snubbed by the King as he arrived at Riyadh airport
Obama has been accused of siding with Saudi over 9/11 victims' families
Families have been pushing Congress for the right to sue Saudi Arabia
Row over whether to declassify 28 pages of papers has intensified
Barack Obama has met with the king of Saudi Arabia in Riyadh to discuss counter-terrorism and the threat of ISIS, just as fresh information emerged that appears to connect the Arab nation and the September 11 attacks.