Howard Unruh was the son of Samuel Shipley Unruh and Freda E. Vollmer. He had a younger brother, James; they were raised by their mother after the parents separated. Unruh grew up in East Camden, attended Cramer Junior High School, and graduated from Woodrow Wilson High School in January 1939. The Woodrow Wilson High School yearbook from 1939 indicated that he was shy and that his ambition was to become a government employee. Always a reserved man, he had turned into a recluse in the three months before his spree. The World War II veteran was unemployed and lived with his mother. During the war, he was reportedly a brave tank soldier who served in the Battle of the Bulge and kept meticulous notes of every German killed, down to details of the corpse. He was honorably discharged in 1945, and returned home with a collection of medals and firearms. Howard Unruh decorated his bedroom with military items, and set up a target range in his basement. His mother supported him by working at a factory while Howard hung around the house and attended daily church services. He briefly attended a pharmacy course at Temple University in Philadelphia but dropped out after three months. He had trouble getting along with his neighbors, and his interactions with them deteriorated in the three months before his spree. He was considered a “mama’s boy” and the subject of teasing. Unruh was harassed by neighborhood teens, who thought he was homosexual and used to make fun of him. He was reported to have been depressed about having had “homosexual liaisons” in a Philadelphia movie theater.

Eventually Howard Unruh became paranoid about his neighbors and started to keep a diary detailing everything he thought was said about him. Next to some of the names was the word “retal.”, short for “retaliate”. He arrived home from a movie theater at 3 am on September 6, 1949 to discover that the gate he had just built in front of his house had been stolen. This appears to have been the trigger; Unruh told the police, “When I came home last night and found my gate had been stolen, I decided to kill them all.” After sleeping until 8 am he got up, dressed in his best suit and ate breakfast with his mother. At some point, he threatened his mother with a wrench, and she left for a friend’s home. At 9:20 a.m., Unruh left the house armed with a German Luger pistol. In only twelve minutes he shot and killed 13 people and wounded three others. Although in general the killings were premeditated, the victims seemed to have been chosen at random. Unruh’s first shot missed its intended victim, a bakery truck driver. Unruh shot two of five people in a barber shop, sparing the other three. One victim was killed when he happened to block the door to a pharmacy. A motorist was killed when his car slowed to view the body of a victim. Intending to kill a local tailor, Unruh entered his shop, but the tailor was not there; Unruh killed the man’s wife. Other intended victims successfully locked themselves inside their businesses (a tavern and a restaurant), and Unruh was unable to reach them. When he heard the sirens of the approaching police, Unruh returned to his apartment and engaged in a standoff. Over 60 police surrounded Unruh’s home, and a shootout ensued. During the siege, Philip W. Buxton, a reporter from the Camden Evening Courier, phoned Howard Unruh’s home and spoke briefly with him. On a hunch, Buxton had looked up Unruh’s number in the phone book. Buxton later recounted the conversation, which was cut short when police hurled tear gas into the apartment.

Howard Unruh surrendered several minutes later. While Unruh was being arrested, a policeman reportedly asked, “What’s the matter with you? You a psycho?” In response, he said, “I’m no psycho. I have a good mind.” Unruh was later taken in for interrogation at the police headquarters, where policemen and Mitchell Cohen, Camden County prosecutor, questioned him for more than two hours. He told the police that he had spent the previous evening sitting through three showings of a double feature, The Lady Gambles and I Cheated the Law, and had thought that actress Barbara Stanwyck was one of his hated neighbors. He provided a meticulous account of his actions during the killings. Only at the end of the interrogation did they discover he had a gunshot wound in the left thigh, which he kept secret. He was subsequently taken to Cooper Hospital for treatment. Charges were filed for 13 counts of “willful and malicious slayings with malice aforethought” and three counts of “atrocious assault and battery”. He was eventually diagnosed with paranoid schizophrenia by psychologists, and found to be insane, making him immune to criminal prosecution. When he was able to leave Cooper Hospital, Unruh was sent to the New Jersey Hospital for the Insane (now Trenton Psychiatric Hospital), to be installed into a bed in a private cell in the maximum-security Vroom Building. Howard  Unruh’s last public words, made during an interview with a psychologist, were, “I’d have killed a thousand if I had enough bullets.”