People in New York trying to help the cops find the shooter
For context, this is from terminator 2 where the protagonist is saved by his best friend in the first 30 min of the film by lying to a terminator cyborg from the future posing as a cop.
Say Nothing by Patrick Radden Keefe could be a good place to start. The central bit being told is about the abduction and murder of a woman, but most of the book is really about the history of the IRA and the Troubles, giving context to the abduction.