The gunman's computer and grim new details
Investigators have so far been unable to retrieve data from a computer taken from the home of the gunman, Adam Lanza, a law enforcement official said Tuesday.
It appears Lanza smashed the computer, extensively damaging the hard drive, the official said, adding that the FBI is assisting Connecticut State Police in trying to retrieve data from the computer.
Lanza's mother was shot four times in the head while she slept in her bed, said Connecticut Chief Medical Examiner H. Wayne Carver, also Tuesday.
Adam Lanza killed himself with a shot to the front of his head from a handgun, the medical examiner said.
Toxicology tests are under way to determine whether Adam Lanza had taken medication.
Growing debate over gun laws
What happened in Newtown should never happen again, advocates on both sides of the gun-control debate agree. But they're at staunch odds about how to turn words into reality.
The National Rifle Association commented Tuesday for the first time since the shooting, saying it was shocked and heartbroken by what happened. The group is planning to hold a news conference on Friday.
"Out of respect for the families, and as a matter of common decency, we have given time for mourning, prayer and a full investigation of the facts before commenting," it said. "The NRA is prepared to offer meaningful contributions to help make sure this never happens again."
The grassroots group Newtown United sent a delegation to Washington to meet with the Brady Campaign to Prevent Gun Violence as well as families from July's movie theater massacre in Aurora, Colorado.
The new group, which formed out of Newtown on Sunday, aims to create meaningful dialogue -- both locally and beyond -- about what may have led to the tragedy.
The debate is playing out not just in Newtown and Washington, but across the United States.
Two national polls conducted shortly after the Newtown massacre suggest that more Americans want stricter gun control.
In a Washington Post/ABC News poll, 54% of adults favor stricter gun control laws in the country, while 43% oppose.
And a new CBS News poll indicates that 57% of Americans back stricter gun laws, the highest percentage in a decade; 30% think gun laws should be kept as they are.
However, less than half of the respondents in the CBS poll -- 42% -- think stricter gun laws would have helped prevent what happened at Sandy Hook Elementary.
Sen. Joe Manchin, a conservative Democrat from West Virginia and a "proud gun owner," said he's now committed to "dialogue that would bring a total change" after the massacre in Newtown.
"Who would have ever thought, in America or anywhere in the world, that children would be slaughtered?" he asked. "It's changed me."
John Licata told CNN's iReport there needs to be better vetting before people buy guns, and assault weapons should be banned -- something Sen. Dianne Feinstein, D-California, says she'll propose once the new Congress convenes in January.