Connecticut's gun laws are some of the toughest in the country, according to anti-gun groups, but they do not specifically ban the Bushmaster AR-15-type guns and the weapon can be easily modified to dodge other restrictions. On Bushmaster's website, the company offers to help customers make sure their assault-style rifles are "state compliant."
"But it's still just as deadly because what makes it dangerous is the ability to take almost unlimited amounts of ammunition and a pistol grip," said Horwitz. "That's what allows the shooter to keep the barrel down on the target."
Forensic psychologist Michael Welner told ABC News today that while the shooting has certainly reinvigorated America's decades-old gun debate, the media has been missing an important part of the lesson from the shooting: the crush of media coverage gives mass shooters exactly what they want.
"If you can keep an assault rifle out of his hands the body count will drop, and that's great, but the mass killings will continue to happen unless, systemically, we do address it as a social phenomenon and recognize that there are things that promote it, for example, his picture on our screen and us even caring to go all the way back to find out what his grievance is..." Welner said. "He's looking for legitimacy... [Shooters] want to go from irrelevance to hyper-relevance."
ABC News' Lee Ferran and Shushannah Walshe contributed to this report.