7:17 p.m. ET: UPDATE: A computer at the Connecticut home where Newtown, Conn., school shooter Adam Lanza lived with his mother was badly damaged, perhaps smashed with a hammer, said police who hope the machine might still yield clues to the gunman's motive.
5:47 p.m. ET: Not even a national tragedy is safe from social media tomfoolery and hoaxes.
After the mass shooting at an elementary school in Newtown, Conn. on Friday, which left 20 children and six adults dead, most of the people who took to Twitter and Facebook were there to share their sympathies and discuss political action.
But some took to creating some online disruption - they created fake Twitter, YouTube and Facebook profiles appearing to be Adam Lanza, the shooter, and his brother Ryan.
2:22 p.m. ET: FLASHBACK: Two months after the January 2011 Tucson shooting, President Obama put into writing the same pledge he made last night in Newtown, Conn. "We have a responsibility to do everything we can to put a stop to" tragedies from gun violence, he said in an op-ed in the Arizona Star.
But in the next sentence, Obama adds this caveat, shedding light on his approach to guns:
"Like the majority of Americans, I believe that the Second Amendment guarantees an individual right to bear arms," he wrote. "And, in fact, my administration has not curtailed the rights of gun owners - it has expanded them."
1:09 p.m. ET: ABC's Dan Harris tweets from Newtown, Conn.:
- dan harris (@danbharris) December 17, 2012
12:15 p.m. ET: The lone survivor of one of the two Sandy Hook Elementary School first-grade classrooms where Adam Lanza allegedly shot and killed 20 children tricked the gunman by playing dead, the girl's pastor said.
10:22 a.m. ET: "Tragedy at Sandy Hook: The Search For Solutions": From gun control and assault rifles to mental illness and school safety, ABC News will explore the questions on people's minds and search for solutions in the wake of the tragic shooting at Sandy Hook Elementary School in Newton, Connecticut with a dedicated week of special programming.
"Nightline" will feature specials editions each night this week.