A 45-year-old man shot and killed eight people, including two young children and a woman who was eight months pregnant, at a home in Erie, Pennsylvania, on Friday before apparently taking his own life, authorities said Saturday.
Erie Police Chief Rick Lorah said seven of the victims were related to the gunman, while the eighth was a family friend.
Investigators have not established a motive for the killings, which left nine people dead, including the suspected shooter.
Police were alerted shortly before 5 p.m. Friday after gunfire was reported near the residence.
Investigators reviewing video and audio evidence identified what appeared to be muffled gunshots inside the house before two distressed women approached the property seeking help.
The women, aged 51 and 37, were subsequently shot outside the home after the gunman emerged, authorities said.
Officers arrived within minutes and discovered both women dead outside.
After deploying a drone and robot, police entered the residence and discovered a five-year-old boy and a one-year-old girl on the first floor.
Four additional victims, two women aged 24 and 44 and two men aged 19 and 21, were found around the stairwell and upper floor.
The suspected gunman was also discovered dead inside.
One of the victims was eight months pregnant.
Lorah said investigators would examine cellphone evidence and interview surviving relatives to determine what preceded the violence.
He indicated that mental health could be a factor but declined to establish a definitive motive.
Pennsylvania Governor Josh Shapiro offered state assistance to Erie Mayor Daria Devlin and expressed condolences to the victims' families.
Devlin addressed grieving relatives during Saturday's news conference, acknowledging the devastating impact of the killings and pledging community support.
District Attorney Elizabeth Hirz urged residents to avoid spreading unverified information while investigators continued examining the circumstances.
Shapiro also referenced the Erie killings alongside the shooting of two Philadelphia police officers early Saturday, describing the events as a particularly dark period for Pennsylvania.