(CNN) -- A man shot and killed two women and another man Tuesday in Bonne Terre, Missouri, before killing himself with a handgun, in what local police said was a domestic dispute.
The identities of the four persons were not immediately released. Bonne Terre is about 60 miles south of St. Louis, Missouri.
Bonne Terre Police Chief Douglas Calvert said at a news conference that the man entered an apartment and shot a man in the doorway and a woman in a bedroom. A toddler, 2 or 3 years old, was found inside the house unharmed, the chief said.
The man then went to a SUV parked outside the apartment and fatally shot another woman while she was apparently protecting another toddler, Calvert said. That child also was unharmed, he said.
Responding police officers came upon the gunman running away from the apartment, authorities said.
"They advised him to drop the weapon. At that point, he took his own life," Calvert said. The suicide occurred outside, near a highway, about 300 feet from the apartment, Calvert said.
The two women and the other man were all apparently living in the same apartment, while the shooter did not reside there, Calvert said.
"There does seem to be some relationship between the victims," Calvert said. "We do believe they did know each other."
Calvert described the four adults as being in their 20s.
One child was a boy, and Calvert couldn't recall the other child's gender, he said.
Police received a call about 10 a.m. Tuesday that a subject was trying to kick down a door and a woman was screaming, authorities said.
The shooting happened at an apartment complex about a half mile from the town's high school and a middle school. All schools were on lockdown for about an hour.