ST. PAUL — Police said a good Samaritan trying to help people following a car crash was one of three people fatally shot in St. Paul in an eight-hour time span.

The 31-year-old man was shot in the head in the Payne-Phalen neighborhood at about 10 p.m. Monday. A 27-year-old driver was detained.

Police spokesman Steve Linders said investigators are trying to determine whether the shooting was connected with two others Monday and early Tuesday.

An 18-year-old was fatally shot AT about 4:30 p.m. Monday on the city’s North End. And, at about 12:15 a.m. Tuesday, a 27-year-old man was shot and later died at Regions Hospital. Linders said the man was in a vehicle with another person when someone in another vehicle began firing at them. Police are working to determine a motive.