Update: Brad Stone's body found in field near his home and military acquaintances recount odd reputation and issues with ex-wife.

A manhunt is underway for a former Marine reservist who prosecutors say went on a shooting spree early Monday killing six family members, including his ex-wife, and wounding a teen in three towns across Montgomery County, Pennsylvania.

Bradley William Stone, 35 of Pennsburg, is considered armed and dangerous. Montgomery County District Attorney Risa Vetri Ferman said police are actively searching for him and residents of one town are being asked to lock themselves indoors.

Stone stands 5-feet-10-inches tall and weighs 195 lbs. He is believed to be clean-shaven, but earlier officials said he could have a red beard and close-cropped hair. He is known to use a cane or walker to assist in moving, Vetri Ferman said. He may also be wearing military fatigues — either green or brown.

The man served more than eight years in the U.S. Marine Corps Reserve and was deployed to Iraq, according to a Marine Corps spokesman. During his time, he earned several medals and his specialty was Artillery Meteorological Man — effectively a meteorologist that monitors weather conditions to ensure military fire accuracy.

Family friends and neighbors who know Stone said he suffered from post-traumatic stress disorder and was discharged from the military because of it.

SWAT officers used military-grade vehicles and equipment to search Stone's home in the town of Pennsburg and the surrounding area. But so far have no definitive idea of where he may be.

"We actually recovered his vehicle and his personal cell phone so we do not have information about how he might be traveling," Vetri Ferman said. She asked for the public to keep an eye out for Stone and call 911 right away if they spot him.

A man, wearing fatigues and fitting Stone's description, attempted to carjack a driver at knifepoint in the Doylestown, Bucks County area shortly before 8 p.m., county dispatchers tell NBC10. The carjacking victim then fired shots at the man as he fled into the woods, officials said.

Police spent four hours searching the area -- locking down the Central Bucks YMCA and Stonington Farms Apartments. Philadelphia Police sent one of their tatical helicopters, equipped with an infrared camera, to the area to help, officials said.

Having turned up nothing, the search was suspended around midnight, but officials asked residents to remain vigilent.

Police investigated four scenes in Montgomery County as part of the shooting spree involving suspected gunman Bradley Stone. Officials said shootings took place at three of the locations -- Harleysville, Lansdale and Souderton. The fourth location, in Pennsburg, is where SWAT officers searched for Stone, near his home. They found his body not far from his home on Tuesday.

Among Stone's seven victims is his former wife, Nicole Hill Stone. She was shot inside her apartment in the Harleysville section of Lower Salford Township, just feet from their kids, around 4:55 a.m., police sources, prosecutors and neighbors tell NBC10.

“I heard the kids say, ‘Mommy no. We need my mom. I want my mom.’ And I heard [the suspect] say ‘Let’s go. We have to go now. We’re leaving,’” the woman’s next-door neighbor, at the Pheasant Run Apartments along 150 Main Street, said.

Moments after being jolted awake by the gunshots and hearing the yelling, the woman saw the children, believed to be 8-and 5-years-old, and a man running to a car parked outside.

“I opened the window and I asked him ‘Is everything OK?’ He just looked at me and said ‘She’s hurt pretty bad. We have to leave. She’s hurt.’ And he just got in the car and just left," she said.

When police arrived, they found the mother dead inside the second-floor apartment, police sources tell NBC10. Two bullet holes dotted the apartment's outer wall.

The children were located safe at the home of Stone's neighbor in Pennsburg, Vetri Ferman said.

Hill Stone was last on her ex-husband's hit list, the prosecutor said.

Stone shot the woman's mother, Jo Anne Koder, and her 75-year-old grandmother, Patricia Hill, inside their home along W. Fifth and Pierce Streets in Lansdale around 4:25 a.m., Vetri Ferman said.

The county's 911 call center received a hang up call shortly before the shooting, she said. Police spent three hours searching the area following the shooting, but turned up nothing.

A check shortly before 8 a.m. at the Souderton home of Hill Stone's sister, Trish Flick, turned up another gruesome scene.

Stone barged into Flick's Penn Avenue home around 3:30 a.m. and shot her, her husband Aaron, their 14-year-old daughter Nina and 17-year-old son Anthony, according to prosecutors.

SWAT officers surrounded the home after arriving and spent hours trying to make contact with a person they could see moving inside.

Around 11 a.m., officers fired a diversionary device into the home and, following the resulting boom, entered. They found all, but Anthony Flick dead. He was rushed to a waiting medical helicopter and flown to Thomas Jefferson Hospital's trauma center in Philadelphia, officials said.

Still, Stone was nowhere to be found.

The situation prompted homes to be evacuated and a shelter in place order to be activated in the town's school district. That was lifted around noon as SWAT officers left the Penn Avenue scene. That house remains under investigation as an active crime scene, Towamencin Township Police Chief Paul Dickinson said.

Those officers, driving a mine-resistant vehicle, then made their way to a fourth home, a duplex owned by Stone, along Main and W. 4th streets in Pennsburg. That home is about 20 miles from Souderton and is where additional SWAT officers had been stationed for hours.

Police broke down a garage door and the front door, fired several gas canisters inside and used a megaphone to say "Bradley, this is the police. Come out now."

After getting no response for hours, SWAT officers moved inside and found nothing. They then expanded their search to areas nearby.

Sources said officials have asked other county law enforcement agencies to send two-men patrol cars to assist in the search. Officials in neighboring Bucks County and the FBI confirmed they are also supporting the effort.

Because of the manhunt, the Upper Perkiomen School District, which serves Stone's town, announced its schools will be closed on Tuesday.

Officials have not released a motive for the shooting, but several of Nicole Hill's neighbors and friends said the woman feared for her life as the two went through a bitter custody dispute.

"She knew and [Bradley] would tell her that he was going to kill her," said friend Evan Weron. "She would go around to all the ladies in the neighborhood 'This man's going to kill me.' She felt threatened."

Contact Vince Lattanzio at 610.668.5532, vince.lattanzio@nbcuni.com or follow @VinceLattanzio on Twitter.