Nine people were injured, including two young children and their mother, after a shooter opened fire at a splash pad in a Detroit suburb where families gathered to escape the summer heat Saturday. Law enforcement tracked a suspect to a home, where the man died by a self-inflicted gunshot wound, authorities said.

An 8-year-old boy was shot in the head and in critical condition Saturday night, Oakland County Sheriff Mike Bouchard said during a news conference. The boy's mother also was in critical condition after being wounded in the abdomen and leg, and his 4-year-old brother was in stable condition with a leg wound.

Authorities initially said they believed as many as 10 people had gunshot wounds from the shooting in Rochester Hills, but that number was revised after they checked with area hospitals.

The other six victims, all 30 or older, were in stable condition, Bouchard said. They included a husband-and-wife couple and a 78-year-old man.

The shooting happened just after 5 pm at a city park featuring a recreation area with a nonslip surface where people can turn on sprays and fountains of water to play in. Bouchard said the attack appeared to be random, with the shooter driving up to the park, walking to the splash pad and firing as many as 28 times, stopping multiple times to reload.

At least one witness reported that the shooter appeared to use two hand guns during the attack, but that has not yet been confirmed, the sheriff said.

In the chaos, “People were falling, getting hit, trying to run,” Bouchard said. “Terrible things that unfortunately all of us in our law enforcement business have seen way too much.”

The gunman was “apparently in no rush. Just calmly walked back to his car,” the sheriff said.

Police heard the 911 call reporting the shooting as it came in, Bouchard said, because the agency uses a service that simultaneously sends emergency calls to first responders. An officer was at the scene within two minutes, he said.

Bouchard said the first deputies who arrived immediately began providing first aid including tourniquets. Officers also were able to quickly come up with a likely address, and a car matching the suspect's vehicle was at the residence.

Deputies surrounded the home and tried to make contact with the suspect inside, to no avail, Bouchard said. They sent a drone inside the home and then entered to find the suspect was dead.

Another weapon was found inside. The quick containment of the suspect may have prevented a “second chapter” to the shooting, the sheriff said, displaying a photo of a semiautomatic rifle on a table inside the home.

The suspect did not live in Rochester Hills and investigators do not yet know why he went to the splash pad, according to Bouchard.

Officials did not release the man's name. Bouchard described him as a 42-year-old white man and said officials believe he lived with his mother. The man's mother was notified, Bouchard said.

“In terms of the why,' I don't know,” Bouchard said of the gunman's motive.

At the splash pad, authorities found a handgun, three empty magazines and 28 spent shell casings. At the home, they recovered a semiautomatic rifle and another handgun believed to have been used by the suspect to take his life, Bouchard said.

Police cordoned off the area with tape and dozens of yellow evidence markers lay on on the ground among colourful folding chairs.

“When I got on scene I started to cry because I know what a splash pad is supposed to be,” a place where people gather and have fun, Rochester Hills Mayor Bryan Barnett said.

The shooting was a reminder “that we live in a fragile place,” Barnett said.

Rochester Hills is about 15 miles (24 kilometres) south of Oxford, where in 2021 a 15-year-old fatally shot four high school students.

Counselling would be made available at a local public service office on Sunday to anyone in need, Bouchard said. The Oxford Resiliency Centre, established to help those impacted by the 2021 shooting at Oxford High School, remains in operation and can assist community members, he said.

“Our most fervent hope, at least at his point, is that all of the injured victims have speedy recoveries,” Bouchard said. “None of us ... anticipated going into Father's Day weekend with this kind of tragedy that families will be deeply affected by forever.”

Saturday's shooting came at the end of the first full week of summer vacation for students attending Rochester Community schools.

Bouchard called it “a gut punch” for the county.

“We've gone through so many tragedies,” the sheriff said. “You know, we're not even fully comprehending what happened at Oxford. And, you know, now we have another complete tragedy that we're dealing with.”

Michigan Gov. Gretchen Whitmer said on the social platform X that she was heartbroken to learn of the shooting and was in touch with local officials.