Data collected for one purpose can always be used for another. Search history data, for example, is collected to refine recommendation algorithms or build online profiles, not to catch criminals. Usually.
Smart devices like speakers, TVs, and wearables keep such precise details of our lives that they’ve been used both as incriminating and exonerating evidence in murder cases. Speakers don’t have to overhear crimes or confessions to be useful to investigators. They keep time-stamped logs of all requests, alongside details of their location and identity. Investigators can access these logs and use them to verify a suspect’s whereabouts or even catch them in a lie.