An investigation assist system includes a server communicably connected to a first camera, one or more second cameras and a third camera; and a client terminal communicably connected to the server. The first camera captures a wide range of an intersection, the one or more second cameras capture identification information of a license plate and a face of a person in a vehicle entering the intersection, and the third camera captures outdoors. The server acquires and performs video analysis on videos thereby holding a video analysis result. The client terminal receives input of notified information including a date and a location on and at which an incident has occurred, determines to start a first investigation process, or a second investigation process, and tracks a suspect with the first investigation process or an escaping vehicle with the second investigation process.