Coming from what was once considered the peak period for movies about crime and police work, ‘The Laughing Policeman’ is worthy of praise and acknowledgment as a well-made, realistic portrayal of how law enforcement officers genuinely function, deal with their routines, and investigate offenses. Walter Matthau, typically recognized for his comedic skills, delivers a strong performance, and Bruce Dern also stands out when he's paired with Matthau after the latter’s regular partner—who had brought an open case home from vacation—is caught up in a violent multiple homicide on a bus. The film presents a carefully crafted story that illustrates how isolated a dedicated police officer can be from their family, how much animosity they often face from the public, and the frustrating setbacks encountered while pursuing justice and ensuring a conviction. It’s like ‘Dirty Harry’ or ‘The French Connection,’ but presented truthfully, rather than as an idealized fantasy of what it's like to be a police officer—though I do enjoy those kinds of films too.

Source on TMDB