But are they denying it because they don't want to stir up trouble? They're denying a lot of obvious stuff too - like saying it was a burglary when the family says jewelry wasn't taken.
Possible, but I doubt it, because if they were lying and the truth eventually came out, as it always does, this would cause an even bigger lynch mob than the one that is already forming.
The police are doing the right thing in being open to all possibilities. It certainly seems possible this family was murdered by Muslims, but there are so many examples of the "obvious" being untrue in criminal cases, particularly where race or religion is involved.