Manhunt grows for Pennsylvania shooting spree suspect
The manhunt has grown for the suspected killer of six people near Philadelphia, officials in the US state of Pennsylvania say.
Schools shuttered and and public buildings increased security as police search for Bradley William Stone, 35.
Mr Stone is suspected in the killing of his ex-wife Nicole Stone, her mother, her grandmother, her sister, her sister's husband and their daughter.
He may be armed and dangerous, authorities warn residents.
"We are accessing every possible resource... to find Mr Stone. We will find Mr Stone," Montgomery County District Attorney Risa Vetri Ferman told reporters on Tuesday.
Authorities from multiple agencies are engaged in the hunt, searching the suspect's car, home and phone for clues to his current whereabouts, she added.
The search has also spread to nearby Bucks County, where a man wielding a knife and fitting Mr Stone's description - red hair and wearing military fatigues - unsuccessfully attempted a carjacking before being chased into a wooded area.
The shootings in Souderton, Lansdale and Harleysville began at about 04:00 local time (09:00 GMT) on Monday.
The first took place at the home in Souderton of Mr Stone's former sister-in-law, Patricia Flick. She was killed along with her husband, Aaron Flick, and the couple's daughter, Nina, 14. The couple's 17-year-old son, Anthony Flick, was badly wounded.
He is currently in very serious but stable condition in hospital, authorities said.
The next shooting was at a house in nearby Lansdale where Nicole Stone's mother, Joanne Hill, and grandmother Patricia Hill were killed.
Nicole Stone was later killed at her home in Harleysville. Neighbours reported seeing Mr Stone fleeing with their two children and raised the alarm.
The children were found safe a short distance away, and Mr Stone's current wife and infant child were also secured.
Reports said the shootings may have been triggered by a custody dispute.
Mr Stone had reportedly filed an emergency motion to the court earlier this month, although those records are currently sealed.
"[Nicole Stone] would tell anybody who would listen that he was going to kill her and that she was really afraid for her life," Evan Weron, a neighbour in Harleysville, told the Associated Press news agency.
Police surrounded a home in Pennsburg on Monday, where the suspect is a resident, and called out by megaphone: "Come to the front door with your hands up. You're under arrest."
But Ms Ferman later told reporters police were still searching for Mr Stone in a number of different locations.