A woman crashed her sport utility vehicle into a woman and her three children early yesterday morning, killing a 5-year-old boy and leaving the mother in serious condition, police officials said.

Bertilde Gabriel, 52, was turning right on Flatbush Avenue from East 28th Street in the Kensington section of Brooklyn when she collided with another SUV at about 7:40 a.m., police said. Her car crossed onto the sidewalk and slammed into the 24-year-old woman and her children, who were on their way to school, police said. She kept driving for another two blocks, where other drivers who had witnessed the incident stopped her, police said.

When police arrived, Ms. Gabriel was unconscious in her vehicle.

An eyewitness, Guadalupe Del Valle, 32, said he saw Ms. Gabriel frantically trying to turn the wheel of the car after the first collision, but she couldn’t regain control of the car.

“I saw the car run over the children,” he said through a translator. “I was scared. I tried to get away.… It hurts my stomach. I feel bad I couldn’t do anything.”

Christopher Frombrum, 5, was killed. His mother, who was not identified by press time, was in serious condition last night at King’s County Hospital. Her 8-year-old son and 6-year-old daughter were in stable condition.

Police charged Ms. Gabriel with criminally negligent homicide and leaving the scene of the accident. She was waiting to be arraigned in Brooklyn Criminal Court last night.

Ms. Gabriel’s daughter, Franklina Gabriel, 17, said her mother had been suffering from heart palpitations for the last month.

“They were making her lose and gain consciousness,” she said. “But she went to get medicine. They said she would be fine.”