Investigators spent the day at the home of 20-year-old Adam Lanza, sweeping the entire house for any evidence of a motive behind his rampage that killed 20 children and seven adults, including his own mother.
There are also new details about Nancy Lanza's whereabouts in the days right before the shooting.
CNN's Deborah Feyerick is OutFront with the latest.
There's been a great deal of speculation about 20-year-old gunman, Adam Lanza's mental and developmental health since the shooting in Newtown that left 28 dead, including Lanza.
Some who knew him say he had Asperger's syndrome - an Autism Spectrum Disorder. But Autism advocacy groups were quick to caution against linking Asperger's Syndrome to the violence.
Bob and Suzanne Wright - grandparents of a child with autism and the founders of Autism Speaks - say: "Autism did not cause this horror. The profound tragedy of these senseless murders will only be compounded if it results in unwarranted discrimination against people with autism."
But according to a leading medical encyclopedia - cited on the National Institutes of Health website - here are some possible behaviors for a person with Autism:
– Shows a lack of empathy
– "Acts up" with intense tantrums
– Shows aggression to others or self
So could Autism have played a role of any kind – if that's indeed what Lanza had?
OutFront tonight: Bob Wright, co-founder of Autism Speaks.
Can a person be born a killer? That's the big mystery surrounding the massacre in Newtown - what caused Adam Lanza to murder his mother, then 26 others at Sandy Hook Elementary School.
Connecticut's chief medical examiner Dr. H. Wayne Carver has asked a geneticist to join in the investigation.
"I'm exploring with the department of genetics what might be possible, if anything is possible. Is there any identifiable disease associated with this behavior?" says Carver.
Is this a case of nature versus nurture?
OutFront tonight: Dr. Drew Pinsky – host of "Dr.Drew" on HLN and a practicing physician and psychiatrist.
Burying the victims of Sandy Hook Elementary is an overwhelming and heart-wrenching task that largely falls on the shoulders of one man.
Dan Honan is the only funeral director in the community of Newtown and in the coming days he will bury 11 of the 26 victims who were shot and killed at the school.
CNN's Poppy Harlow has the story.
President Obama's pledge to "use all the powers of " his office to prevent another tragedy like Newtown. On Wednesday, he appointed Vice President Biden to lead a task force on gun control - and report back with recommendations by the end of January.
"This is not some Washington commission... 6 months read and pushed aside, these are real reforms right now," Obama said.
The president said he would push to make sure Congress acts on those recommendations. This may be on the fast-track by Washington standards - but there are some things the President could do even sooner.
CNN Contributor John Avlon has the story.