No he wasn't. He is running for President. Candidates for President do not simply converse. And he wasn't just lamenting on something terrible. He said the local police's handling was "terrible". So he was butting into a local police matter which is irrelevant to his mission to get elected President.
But what he could have said was that the justice department has no business getting involved in a local police matter. He could have used the issue to attack liberal politicians instead of a local police dept.
Rick Santorum does just converse. It’s gotten him in trouble before and it will again. He shares his unvarnished opinion.
Say what you will about the Martin case, but it is odd that they let the shooter of a teenager walk out the door.
They had no real reason to believe him.