PENNSBURG, Pa. » A man suspected of going to three houses in the Philadelphia suburbs and fatally shooting six people, including his ex-wife and her 14-year-old niece, was at large Monday night, and a prosecutor said investigators didn’t know where he was or how he was getting around.

Police recovered the cellphone and car of Bradley William Stone, who had recently been in court fighting with his ex-wife over custody of their two children. SWAT teams surrounded his Pennsburg home and pleaded through a bullhorn for him to surrender, but Montgomery County District Attorney Risa Vetri Ferman said it was unclear if he was there.

"As I stand here right now, we do not know where he is," Ferman told reporters at an evening news briefing.

The shooting rampage started before dawn at the home of Stone’s former sister-in-law in Souderton and ended about 90 minutes later at ex-wife Nicole Stone’s apartment in nearby Harleysville, Ferman said, correcting a timeline that had been based on when the crime scenes were discovered.

Nicole Stone’s sister, Patricia Flick, her sister’s husband, Aaron Flick, and the couple’s 14-year-old daughter, Nina Flick, were killed in the first wave of violence, which wasn’t discovered until just before 8 a.m., Ferman said.

Their 17-year-old son, Anthony Flick, was pulled from the home with a head wound around 12:30 p.m. and was taken in an armored vehicle and then by helicopter to a Philadelphia hospital for treatment.

Nicole Stone’s mother, Joanne Hill, and grandmother Patricia Hill were killed next at their home in nearby Lansdale. Investigators were alerted by a hang-up call to emergency dispatchers, Ferman said.

Nicole Stone’s neighbors at the Pheasant Run Apartments in Harleysville said they were awoken around 5 a.m. by the sounds of breaking glass and gunshots coming from her apartment. They said they saw Stone fleeing with their two children and alerted authorities.

"She would tell anybody who would listen that he was going to kill her and that she was really afraid for her life," neighbor Evan Weron said.

The two children Stone took from his ex-wife’s house were safe, Ferman said. She did not say anything about what weapon or weapons were used.

Stone, who’s white, about 5-foot-10 and 195 pounds, was likely wearing military fatigues and was known to use a cane or walker, but it’s possible he did not need them, Ferman said.

Harleysville, Lansdale and Souderton are within a few miles of each other. Police with armored vehicles and rifles moved to Pennsburg after spending several hours outside the home in Souderton where several victims were found.

Several school districts ordered students and teachers to shelter in place.

"Everything started being blocked off, the SWAT was then later called in, then we had the tanks pull up," said Don Smith, describing the scene near his Souderton home.

Brad and Nicole Stone married in 2004 and filed for divorce in March 2009, according to court records.

Brad Stone, 35, remarried last year, according to records. Nicole Stone, 33, became engaged over the summer, neighbors said.

The former had couple sparred over custody of their two children, with Brad Stone filing an emergency petition Dec. 5 and Nicole Stone responding with a counterclaim Dec. 9. The outcome of their dispute was unclear.

Weron, the neighbor, said Bradley Stone is a military veteran. Court records show he recently faced several driving under the influence charges, one of which was handled a year ago in veterans’ court.

Weron said Nicole Stone would talk frequently about the custody dispute.

"(Nicole) came into the house a few times, a few separate occasions, crying about how it was very upsetting to her," Weron said.

Dale reported from Harleysville. Associated Press writer Kathy Matheson contributed from Souderton and Harleysville.