The shootings started around 6 a.m. inside a home in Sanford, about 30 miles north of Orlando. Police said Allen Cashe, 31, opened fire a few hours after officers had been called to break up a dispute over keys to a vehicle between him and his girlfriend, Latina Herring, 35.
Cashe killed Herring and critically wounded her two sons, aged 7 and 8, and her 60-year-old father, Sanford police spokeswoman Bianca Gillett said.
One of the children was “fighting for his life,” she said.
“This is one of the most horrific crime scenes our officers and investigators have had to encounter,” Gillett told a news conference, where she declined to discuss a motive for the shooting.
After leaving the home, the suspect shot two bystanders, an 18-year-old high school student waiting at a bus stop and a 43-year-old man near some baseball fields, police said in a statement.
The student and the man were in stable condition, Gillett said.
Police, who had been following Cashe after he drove away following the shootings, apprehended him after he left his vehicle and tried to run away, authorities said.
He was charged with first-degree homicide, four counts of attempted first-degree premeditated homicide and one count of second-degree attempted homicide.
It was unclear whether Cashe had lived with his girlfriend in Sanford.
Gillett said Cashe had a long arrest history. It was not immediately known if he had an attorney.