Police did not immediately release the names and ages of the victims or suspects. Investigators are trying to find out why the killings took place, she said.
“We would not believe it was random, but we just do not yet have details on the ‘why’ or ‘what happened,'” Hamlin told reporters.
Police on Tuesday about 01:30 received a call about people in Muskogee, a city of about 37,000 residents, about 40 kilometers drive southeast of Tulsa, was shot.
“When (officers) arrived, they saw a suspect leaving the residence with a gun in his hand. One of our officers shot at that suspect and missed him,” Hamlin said.
The suspect ran, but officers arrested him after a brief chase, Hamlin said.
Inside the house, officers found four children and a man dead, along with an injured child and the injured woman – who were all shot – police said.
The injured child and woman were taken by helicopter to a Tulsa hospital, where the child was pronounced dead, Hamlin said.
Police are being treated in hospital for life-threatening injuries.
Investigators believe the victims were a family, Hamlin said. Investigators do not know if the suspect is related to them, she said.
The suspect was detained in Muskogee County Jail on Tuesday morning, according to Hamlin.