Sci Fi stories that might be set in the near-future or distant future where technology aids both law enforcement and criminals. The stories feature a mystery to solve and some detective type hero, who might just be some lone, down and out police/investigator/war hero/special agent who may or may not have souped up bioengineered capabilities.
A specific form of detective story that merges film noir with the classic American detective novel. A good visual representation of hardboiled sci-fi would be Blade Runner. Hardboiled usually features a cynical down-and-out lone detective who faces some sort of conspiracy mystery investigation. The setting is often seedy bars, crime infested neighborhoods, or a squeaky clean corporate setting. The science fiction aspect adds future tech, usually in the form of bio-engineered body upgrades that give the detective (and criminals he faces) enhanced abilities. Hardboiled Science Fiction is often part of the Cyberpunk tradition.