As relatives began to say their final goodbyes to their slain children, investigators in Connecticut worked Monday to better understand what happened to them, including digging deeper into the gun and computer use of the 20-year-old man who ended their lives.

In recent days, authorities have established that Adam Lanza shot open an entrance into Newtown's Sandy Hook Elementary School. He fired multiple magazines -- each one with 30 bullets -- from a Bushmaster AR-15 rifle to kill six adults and 20 children from two classrooms. Each victim was shot multiple times before Lanza used a handgun to kill himself.

Why? Authorities haven't given a motive. But they are looking into shards of the remnants of the shooter's smashed home computer -- -- including e-mails he may have sent and websites he may have visited -- hoping it will shed light on his thinking, a law enforcement official said Monday.

Authorities are also probing Lanza's history with firearms. The three weapons found near his dead body were the semiautomatic .223-caliber rifle made by Bushmaster and two handguns made by Glock and Sig Sauer. A shotgun was found in his car nearby, according to Connecticut State Police Lt. J. Paul Vance.

The weapons belonged to his mother, Nancy Lanza, who was found shot dead in her Newtown home Friday. She collected firearms, shot them and went to gun ranges, Bureau of Alcohol, Tobacco, Firearms and Explosives spokeswoman Debora Seifert said Monday.

The mother and the son who killed her even went to a range together. From what the ATF has been able to determine thus far, "their most recent visit was more than six months ago," Seifert said.

Beyond such developments, officials overall were tight-lipped Monday about their investigation. Hundreds of state troopers, detectives and other law enforcement personnel are analyzing every round of ammunition fired, examining the gunman's medical history and talking to witnesses, said Vance, the state police spokesman.

Investigators plan to interview a pair of adults wounded "in their lower extremities." The hope is the two -- whom authorities have not identified, though a parent last week said one was a vice principal at the school -- could, "when it's medically appropriate," play a key role in helping to reconstruct what happened, said Vance.

"I'm not at liberty to discuss any of the information so far uncovered, but suffice it to say ... we will cover every single facet," the police spokesman said of the investigation.

First funerals and addressing 'the unthinkable'

The anguish caused by the shooting was visible Monday outside a Newtown funeral home, as young and old streamed in to pay their respects to 6-year-old Jack Pinto.

One of the sports fanatic's idols, New York Giants receiver Victor Cruz, paid tribute during his game Sunday by writing "Jack Pinto My Hero" on his cleats. Afterward, the NFL player said he is "amazed" Jack's family chose to bury the boy wearing a child-size Cruz jersey.

"I don't even know how to put it into words," Cruz said.

The 6-year-old himself was a budding athlete. Shortly before his death, he wrestled in his first match and earned a medal, said New Milford Youth Wrestling Association President Ken Linder.

Many of his teammates wore medals into Jack's funeral Monday. Others, many of them about his age, came in Newtown youth sports shirts. The funeral home couldn't contain the mourners, with the line extending to the street.

Jack wasn't the only one remembered Monday. So, too, was Noah Pozner, another 6-year-old whose family said he could get what he wanted just by batting his long eyelashes.

Noah loved playing with his siblings, especially his twin sister. They still don't know how their brother died, Noah's aunt said.

"How do you tell them that's how their brother died?" Victoria Haller said Sunday. "It's the unthinkable, really."

More funerals are coming. For instance, there's Jessica Rekos on Tuesday. Benjamin Wheeler on Thursday. Madeleine Hsu on Friday. All of them are 6 years old.

And once everyone is buried, residents say it's unlikely their tight-knit community will ever be the same.

"It's incomprehensible, the pain here," Darla Henggeler said. "You can't imagine. We're still in shock. I can't let my heart go there because it's so overwhelming.

"Once it settles in, I think my heart will break."

Ex-school official: Lanza would 'withdraw into his own little world'

When he was the Newtown public schools' director of security, Richard Novia knew Adam Lanza. In high school, the then-teen had psychological issues and would sometimes "withdraw into his own little world," Novia said.

But he never saw Friday's carnage coming.