Not exactly a detective mystery, but according to a slide dated June 2012 from a NSA PowerPoint presentation (see: Glenn Greenwald’s site), NSA used some kind of Skynet AI technology to analyze and detect suspicious patterns from location and communication data in order to create a watch list of suspected terrorists. This helped to track associated members of Al-Qa’ida as well as the Muslim Brotherhood. And I'm sure their AI solved a lot of mysteries and found some controversial figures.
Source: U.S. Government Designated Prominent Al Jazeera Journalist as a member of AI Qaeda
For more details check: SKYNET: Courier Detection via Machine Learning for courier detection data and charts generated by analyzing GSM metadata using machine learning algorithms. Also Applying Advanced Cloud-based Behavior Analytics.