Adam Lanza had hundreds of rounds and used multiple high capacity magazines when he went on a rampage at Sandy Hook Elementary School, killing 20 first graders and six adults, Connecticut State Police said today.
After shooting at victims in two classrooms and a hallway with a high-powered semi-automatic rifle, he put a bullet into his own head with a handgun.
"The weapon that was utilized most of the time during this horrific crime was identified as a Bushmaster AR-15 assault weapon," Connecticut State Police Lt. Paul Vance said. "The trajectory of the shots and all of the ammunition used in the horrible crime will be examined."
Vance said three weapons were found at the scene, while a fourth, a shotgun, was recovered from Lanza's vehicle.
While the shattered community of Newtown awaits President Obama's visit this afternoon, plans for the first funerals were announced.
Noah Pozner, the first grader whose twin sister survived the massacre, and 6-year-old Jack Pinto, will be laid to rest in separate ceremonies Monday afternoon.
The funeral for Jessica Rekos, 6, will be held on Tuesday at St. Rose of Lima Roman Catholic Church, where several of the victims' families attend mass.
The community faced a new shock today when parishioners attending the midday service at Rose of Lima were told to evacuate after a church official became aware of a credible threat.
About 1,000 people were gathered inside the church at the time observing one of four memorial services being held there.
Witnesses said police entered the church and told parishioners that a threat had been made against the church and the surrounding area and that everyone had to leave immediately.
More than a dozen state troopers armed with assault rifles entered the church's education center next to the church, but after a short time it was determined that threat was over.
Brian Wallace, director of communications for the Diocese of Bridgeport, said that after massacre on Friday, he felt evacuation was a vital precaution to take.
"I don't think any of us could be surprised about anything after what has happened," Wallace said.
Meanwhile, police are working to understand what set Lanza off on his rampage.
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ABC News has learned that investigators have seized computers belonging to the 20-year-old from the home he shared with his mother Nancy, the same place he killed her before going to the Sandy Hook Elementary School, where he slaughtered students in two first-grade classes and teachers and staff.
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Authorities are forensically investigating those computers and are also examining devices owned by Ryan Lanza, the gunman's older brother, to see if they can learn anything more about Adam and what caused him to snap.
Members of the community gathered today at churches across the small town, seeking comfort, clarity or just a cry.
With intermittent freezing rain falling, the bells tolled at St. Rose of Lima as parishioners came for the morning service.
Little more than a week before Christmas when congregants celebrate the birth of the savior, they instead were mourning the deaths of people they knew.
Many of the victims attended the church and the clergy is preparing for the funerals of eight of the children.
As parishioners arrived at the church for the morning service, many stopped at a makeshift memorial with flowers, teddy bears and candles. On large white boards, people wrote notes that express condolences, hope, and even forgiveness.
One says "Rest in Peace Sweet Angels."
After a man and woman knelt down at the memorial -- the woman overcome by grief crying into her husband's arms -- two police officers opened their cars with a delivery: bouquets of flowers and teddy bears stacked in the back of their vehicles. They delicately placed each one down and then both knelt down at the vigil.
The female officer began crying and her male partner put his arm around her to comfort her. She quickly got up, walking to her car while wiping away tears, and then they pulled away.
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A mother and two young daughters came next. She gripped one while she also wiped away tears. A father and his young daughter also came up, the father kneeling and talking to the girl before they slowly walked into the church.
A state police trooper was also among those dropping flowers at the memorial comprised of candles, stuffed toys and a sign that says "Sleep in heavenly peace."
Police Tracing Guns Used in Shooting
At a news conference this morning, Vance said there are many pieces missing in the investigation and investigators continue to work inside Sandy Hook Elementary School to collect evidence.
Key to the investigation will also be the four firearms found at or near the crime scene, he said.
"We are tracing them historically, all the way back to when they were on the workbench being assembled," Vance said.
Authorities are wrapping up their processing of the exterior crime scene, which included vehicles parked in the school's lot at the time of the shooting, Vance said, and have began to release the cars back to their owners.
Vance declined to say what evidence has or has not been collected.
"We can't take segments of an investigation and discuss that publicly because something taken out of context could be misinterpreted," he said, adding that in the end, the "goal is to answer every single question.