Diata R. Crockett, 34, was charged with first-degree murder, second-degree domestic assault and armed criminal action, according to the office of the circuit attorney of the city of St. Louis.
He was also charged with two counts of child endangerment, unlawful use of a weapon (shooting from a motor vehicle) and unlawful possession of a firearm, all Class C felonies.
Crockett turned himself in through his attorney, Dotson said.
Scott Rosenblum, Crockett's lawyer, told the St. Louis Post-Dispatch
: "He's devastated over the loss of his son. Obviously, there's much more to the story."
The shooting occurred Tuesday night in north St. Louis after Crockett forced his wife and three of their six children into a rental car, Police Chief Sam Dotson said. When the car slowed at one point, the wife jumped out, Dotson said.
"The suspect ... fires one shot at her while she's exiting the vehicle with the 8-month-old in her arms," the chief explained. "The shot strikes the 8-month-old and it's a fatal wound."
The wife ran with the child, Reign Crockett, until a passing motorist stopped, picked them up and began to drive them to a hospital.
Diata Crockett tried to force the vehicle off the road, police dispatchers were told. When the mother arrived at the hospital, Reign was pronounced dead.
According to a probable cause statement, Crockett's wife told him she wanted a divorce. He allegedly hit her with a 9 mm handgun during the fight in the car. The wife, identified only as S.C., said her husband told her he was going to kill her and himself.
She feared he was driving them to a secluded area where he had taken her before.
Suspect is 'devastated'
Police searched for Crockett and the two other children, who were last seen inside his vehicle. Those children were found safe Tuesday night at a relative's house, police said in a statement posted on Facebook
. Police said they were 2 and 3 years old.
The car driven by Crockett was later found at an apartment complex in the town of Ferguson, police said, about 9 miles from the site of the shooting.
Court records show Crockett had been sentenced in 2006 to a year in prison on burglary and assault charges. In 2015, he was sentenced to five years in prison on a drug charge, unlawful use of a weapon, resisting arrest and forgery.
CNN affiliate KMOV
said Crockett's mother had appealed for her son to surrender.
"You need to turn yourself in," said Casetta Crockett. "Talk to your attorney and come in ASAP. You have to set the record straight. We know you love your kids and you would never hurt them, so we know this was a horrible accident. You have to come in, if nothing else, you have to come in for your other kids."