Pennsylvania police hunted for a suspect in the killing of six relatives whose bodies were found on Monday in towns around Philadelphia, the Montgomery County district attorney's office said.
Police were concentrating the search for Bradley William Stone in and around Pennsburg, Pennsylvania, the district attorney said in a Facebook post.
Residents were advised to remain indoors with their doors locked, it said. Pennsburg is about 50 miles (80 km) northwest of Philadelphia.
"Stone should be considered armed and dangerous," the post said.
Stone was being sought in the shooting deaths of six people and the serious wounding of another, it said.
Heavily armed police surrounded a house in Pennsburg and were using a loudspeaker to urge Stone to surrender, shouting: "Bradley, come out with your hands up," according to local media.
Stone was described as being 5 foot, 10 inches (178 cm), 195 pounds (90 kg), with a reddish beard and mustache, and closely cropped hair.
He is believed to be a Marine veteran who suffers from post-traumatic stress disorder, local media said. Stone is known to use a cane or walker and may be wearing military fatigues, authorities said.
All the victims were related to Stone, a 35-year-old resident of Pennsburg, the district attorney said.
The shooting deaths took place at three places in Montgomery County outside Philadelphia on Monday morning.
The first report of a shooting came around 4 a.m. in Lower Salford where police found a woman fatally shot, local media reported.
The victim was believed to be Stone's ex-wife, neighbors told The Morning Call newspaper.
The two had been in a custody battle over their two young daughters, according to NBC10 Television.
A neighbor told the television station she saw a man leave with the girls.
The children later were found safely, local media reported.
About half an hour after the Lower Salford shooting, police responding to a second call found two people shot and killed in Lansdale, about six miles (10 km) east of Lower Salford. Two more people were found dead in Souderton, about six miles (10 km) northwest of Lansdale.
A teenager was taken out of the Souderton home on a gurney and taken away in an ambulance, local media reported.
No details were available about the sixth death.
