A shooter identified by police as Michael William Nash opened fire at a public park in the Detroit suburb of Rochester Hills, Michigan, on Saturday afternoon, injuring nine people.

The 42-year-old man, who was reported to be suffering from mental health issues, was tracked to his home in nearby Shelby Township where he had apparently shot himself to death, authorities said.

Oakland County Sheriff Mike Bouchard said at a news conference Saturday night that among the wounded were an eight-year-old boy, who was shot in the head, his four-year-old brother, who was shot in the leg, and the two boys’ mother, who was wounded in the abdomen and leg.

The other six victims were 30 or older, including a husband and wife couple and a 78-year-old man. Two of the victims including the eight-year-old boy are in a critical condition while the others were reported to be in stable condition.

Police said Nash drove to the park just after 5 p.m., walked over to the splash pad—a recreational area where people can enjoy water sprays and fountains—and opened fire at random. He reportedly used a 9mm Glock handgun, fired it as many as 36 times and stopped to reload more than once.

After the shootings, Nash walked calmly back to his car and fled the scene. Police said he left his weapon behind, the registration of which they used to track him to his residence. The Associated Press reported, “Deputies discovered a handgun next to the body and a semiautomatic rifle on the kitchen table. [Sheriff] Bouchard said Saturday that Nash may have been planning a ‘second chapter’ to the shooting.”

Speaking to the Detroit News, neighbors described Nash as a “loner” who lived with his mother. One neighbor said the man’s mother was “super friendly and nice,” but Nash rarely left the house. “And when he did, he didn’t even say ‘hi’ back to us when we would acknowledge him. He was very quiet and didn’t want to be a part of our community.”

Bouchard said Nash had no prior criminal record. According to published interviews with his mother, the sheriff said, it appears that Nash was, “Walking around the house with weapons … and talking about how the government was tracking him.”

Local and state politicians took to social media to issue their customary hand-wringing comments. Republican US Rep. John James, who lives in Shelby Township and represents Rochester Hills in Congress, said gun violence is an “American epidemic that we need to fix.”

Democratic Secretary of State Jocelyn Benson wrote on Twitter/X that “Kids deserve to be safe from gun violence,” and “Whatever we are doing, it’s not enough.” Democratic Party Gov. Gretchen Whitmer said on Twitter/X that she was “heartbroken” and was in touch with local officials.

The Rochester Hills mass shooting was one of at least 14 such incidents in the US over the Father’s Day weekend:

• In Lathrup Village, Michigan, a residential neighborhood outside of Detroit, six people were shot at a house party at about 12:20 a.m. on Saturday. Police said someone showed up at the party and started shooting. Four suffered non-life-threatening injuries while two were taken to a local hospital and are in critical condition. All of those shot were in their late teens or early 20s. Police also said it appeared to be a targeted attack but no one has been apprehended.

• In Methuen, Massachusetts, north of Boston, eight people were injured at a gathering of hundreds of people known as pop-up party or car club meet-up in an industrial park. Seven people were struck by bullets while an eighth was injured in the mayhem at the scene. The victims were ages 17 to 23. Essex County District Attorney Paul Tucker said the event was part of a series of similar social media Snapchat gatherings where there is loud music, drinking and partying. Police are looking to surveillance video to find out who fired a weapon. “We are actively pursuing all leads in this case,” Tucker said.

• Sixteen people were shot Saturday during a Juneteenth celebration at Old Settlers Park in Round Rock, Texas, two of whom were killed. Police are pursuing a suspect, who they say is armed and dangerous. The shooting began during an altercation between two groups near the vendor area of the event at around 10:50 p.m. Lyndsey Vicknair, 33, from Manor and Ara Duke, 54, from Pflugerville, neither of whom was involved in the altercation, were killed in the shooting, according to Round Rock police. The 14 others who were wounded were between the ages of 14 and 62 and were taken to area hospitals.

• There were multiple shootings in Chicago that resulted in the death of nine people—including a 13-year-old boy—and the injury of 71 others between Friday night and Monday morning. The most violent weekend in Chicago so far this year, the ages of the victims were between 13 and 59. Two of the incidents were mass shootings within an hour of each other. Seven people were shot during a shoot-out on Chicago’s South Side at 2 a.m. Monday morning. In another incident about an hour earlier, five people were injured at a gathering in West Humboldt Park on the city’s northwest side.

• On Saturday night, a shooting in Detroit left one woman dead and injured four others in the city’s east side. Police responded to a call at 11:30 p.m. and found four females, ages 14 to 20, and a man in his 20s all shot. The circumstances surrounding the shooting are unknown, police said, although the suspect is at-large.

• Other mass shootings took place in Cincinnati and Columbus, Ohio; Fort Lauderdale, Florida; Pine Bluff, Arkansas; South Bend, Indiana; Tuskegee, Alabama; Philadelphia, Pennsylvania; and Princeton, West Virginia.

Chris Dennison, a sociology professor at the University of Buffalo who researches crime, told the Associated Press (AP) that “the arrival of seasonable weather presents more opportunities for crime and violence, amid heightened concerns about mental health issues and destructive outcomes.”

Brian Higgins, a lecturer at John Jay College of Criminal Justice in New York, told AP that summer heat, large social gatherings and alcohol consumption typically fuel a seasonal increase in violence in the United States. Higgins said, “This is to be expected. Is it worse than other years? That remains to be seen.”