I believe that the only authority delegated was to Judge a criminal act and to punish a criminal act. However, if you look upon the authority of the various Sheriffs, one would automatically assume that they have a duty to 'prevent crime' that is being committed in their presence.. of course we all have that duty to aid our neighbors/brothers/sisters/etc.

I have read several articles regarding and I believe entitled "Does the police have a requirement to protect you?" From the content of those articles, it would appear that there is no duty imposed requiring them to protect you (prevent crime).

Jerry