The Erie County sheriff says he's done making public comments about a cellphone surveillance device used by his police agency to gather information on persons of interest.

Sheriff Tim Howard told WGRZ Thursday that he won't publicly discuss the matter any longer because doing so could adversely impact investigations.

A stingray is a device that mimics a cell tower and thereby tricks all wireless devices on the same network into communicating with it.

Howard told Erie County legislators last week that the stingray surveillance device his office has owned since 2008 is used only for tracking a person's movements, not for gathering content of cellphone communications. The surveillance equipment can capture data from targeted cellphones even when they're not in use.