Actually, there is attribution.
Originally Posted by Erod
The very next sentence reveals the attribution:
As the Obama administration and the American public have focused their attention on ISIS in recent weeks, conservative groups and leading Republicans have issued stark warnings like those that ISIS and other extremists from Syria are planning to enter the country illegally from Mexico. But the Homeland Security Department, the F.B.I. and lawmakers who represent areas near the border say there is no truth to the warnings.
I hope that helped
Let me know if I can clear up anything else.