What is the fine-grained topic of the following text: The homemade bomb in a Nissan Pathfinder at Times Square did not explode  as a result,a trove of evidence was left behind for investigators to pore over,not only for physical evidence or forensic clues,but also as a reflection of an assailants methods,mind-set and motives. Only return the topic.
Investigation of a failed homemade bomb in Times Square