Strange Behavior (1981) on Netflix

Widowed John Brady is the Chief of Police in small town Galesburg, Illinois, where he has lived most of his life. His only offspring, Pete Brady, is a bright high school senior. John has been in turmoil since the suspicious death of his wife Catherine years earlier, which he always believed had something to do with her boss, Dr. Le Sange, who himself died shortly after Catherine's passing. Only recently has John and Pete's home life gotten back on track with John dating Barbara Moorehead, a waitress at the local hangout, she who has known John for some time. John's life takes a turn for the worse when he has to investigate the brutal slashing murders of four townsfolk in four separate incidents. A brief eyewitness statement to one of the murders before the eyewitness herself is murdered is the only substantive evidence. However, the three other victims were the sons of long time friends of his. Those three friends have a special connection to John's past. As such, he believes if the pattern holds true that Pete may be the next intended target. What John is unaware of is that Pete, who has been trying to earn a little extra money in nearby Galesburg College in the Psychology Department with Mrs. Gwen Parkinson, is not the next target but that he unwittingly has a connection to the next intended murder.