Starring Hollywood legend Dick Van Dyke as Dr Mark Sloan - a medical doctor who solves crimes with the help of his son, a homicide detective (played by his real-life son Barry) - Diagnosis Murder mixes murder mystery with doses of humour. Known for his brilliant analytical mind, Dr Sloan often helps out the local police department as a consultant, and is famed for using his skills to help friends in need. And wouldn't you just know it... there's always a friend who needs help around every corner.