Four children and an adult woman were killed and a child seriously wounded in a shooting rampage in the midwestern US city of Cleveland, Ohio, police said.
Police early on Friday swarmed a section of west Cleveland searching for the suspect, who they identified as Davon Crawford, 33.
Patrol cars blocked area streets and a helicopter hovered above as officers spread out in their search.
All but one of the victims are children, Cleveland Police Lieutenant Thomas Stacho told reporters.
"From what I understand he (Crawford) is the father of some of the children," Stacho said.
Two of those killed were twin toddlers, media reported. Police have not released any names of the victims.
Police said that a child fled the middle-class neighborhood home where the shooting took place around 8:00 pm on Thursday (0100 GMT Friday) calling for help. By the time officers arrived the suspect had fled on foot.
The local newspaper, the Cleveland Plain Dealer, reported that one of the victims was the mother of the children.
Crawford has a violent history, including a 2002 prison stint on a domestic violence event that also involved a gun and children, The Plain Dealer reported.
Police said that Crawford was armed with a semi-automatic weapon.
"Right before we left there they were on their bikes playing," a neighborhood female resident told Cleveland Fox network affiliate WJW Channel 8.
"Then I get home and the little eight-year-old comes up and hugs me ... calling for help," said the woman, who broke down in tears and did not give her name.
A woman named India Cobb, who identified herself as Crawford's cousin, told WJW that the suspect had earlier given no sign of anger.
"It didn't seem anything was wrong or anything like that," said Cobb. "He just got married on his birthday; his birthday was (March 2). He just had a baby girl. I don't understand what went wrong. I don't know what happened. I'm still trying to find out myself."
Cleveland Mayor Frank Jackson, who visited the crime scene, "wishes to express his condolences to the family and friends of the victims," his office said in a statement.
Jackson also praised the city police and said "that he is confident that we will get the man responsible for this heinous crime," the statement read.
Crawford lives and works in a different part of town but frequents the West Side neighborhood where the shooting took place, police said.