Around 11 p.m., the hostages were free after the suspect, 34-year-old Rodrick Shonte Dantzler, shot himself in the head, Police Chief Kevin Belk said.
Belk said officers were in the house, talking to Dantzler, who had been threatening to shoot the two hostages who remained and had asked officers to shoot him -- before suddenly committing suicide.
"It does not make sense," Belk said shortly before midnight. "I don't think you can make sense out of something like this."
The hostages -- one, a 53-year-old woman, had been released earlier -- were unharmed.
Earlier, the discovery of the bodies -- four in one home and three in another across town -- led police on a high-speed chase into downtown Grand Rapids and along I-96 in an attempt to capture the suspect.
City police, Kent County deputies and Michigan State Police in squad cars and a helicopter followed Dantzler, who caused a crash at Fulton and Division in downtown Grand Rapids.
As the chase began, Belk said, two other people were shot, but not fatally. Dantzler also repeatedly shot at police, Belk said, though no officers were hurt.
"It's an awful situation," Mayor George Heartwell said after the bodies were found.
At one point during the chase, the suspect crossed a wide grassy median on the interstate and drove the wrong way down the highway with more than a dozen squad cars in pursuit. Hours later, the highway remained closed.
Dantzler then reportedly ditched the Chevy Suburban he was driving and ran to a home in the 4200 block of Elmdale, near one of the crime scenes in the 1200 block of Brynell Court.
State Corrections spokesman Russ Marlan said records show Dantzler was discharged from the Michigan Department of Corrections in 2005 after serving time for assault less than murder. He had not been under state supervision since then, Marlan said.
A motive remained unknown through it all, though Belk said Thursday night that Dantzler had a "prior relationship" with at least one person at each home where the victims were killed.
An autopsy would be conducted on Dantzler's body today, Belk said.
The day of gunshots and hot pursuit turned parts of normally placid Grand Rapids into a wild place.
Sandra Powney, who lives across the street from one of the homes where the shootings happened, said she had seen Dantzler at the ranch house. She said a couple have lived there for more than 20 years with their two adult daughters.
"I've seen him there. He would come periodically," she said. Powney said she had been at home all day and didn't realize anyone had been killed until police converged on the cul-de-sac about 3 p.m.
"For a while, we couldn't come outside," she said. "They didn't know if there was someone still inside the house."
Sonia Bergers said Dantzler lived in the home with a woman she assumed was his wife and their daughter, a girl who appeared to be about 10 years old.
Mary Lahuis said she and her husband had returned home after having coffee at a nearby fast-food restaurant.
"We were in the house, and police went down our street, running with guns," she said. "They told us to get in the house."
Lee Roedema found himself stuck on westbound I-96 as the suspect's white SUV came "flying past," followed by a phalanx of police cars.
"We knew from the radio that he might be coming this way, but we were already on the expressway and trapped," Roedema said.
Other people told of shots being fired downtown. A shot-up police car with a shattered windshield was left sitting on a street.
"This is just insane," said a woman who declined to give her name.
Lisa Schenden lives with her husband and their children, ages 11 and 8, two blocks from the home where four people were killed. She said the homeowners are a couple whose daughter has a daughter with the suspect.
Schenden said she did not hear the shooting either, but she saw the suspect and his daughter drive up to the house earlier in the day.
"Just last night, my kids went over there swimming, and I went over with them," she said.