The answer to this question is simple: No. Police officers and other members of investigative law enforcement have every right to ask you to speak with them about anything. It is your right not to talk or answer questions they may have for you.
The job of a law enforcement official is important and should not be discounted. Members of law enforcement should be respected because they have committed themselves to protecting you and the community. Still, if you are confronted by an officer and are uncomfortable speaking about any matter, regardless of whether you know anything or not, simply tell the officer that you are unwilling to speak with them without the assistance of an attorney. No one is above the law, and the Constitution of the United States commands that law enforcement officials cease questioning upon the request of legal counsel.