HARTFORD — An expert told a commission looking into the Sandy Hook Elementary school massacre in Connecticut on Friday that there is no data linking autism with increased violent criminal behavior.

"Having autism, having an autism spectrum disorder, having Asperger's syndrome does not mean you are likely to commit a violent crime," said Matthew Lerner, a professor of psychology at Stony Brook University.

Lerner was among a group of experts who testified Friday about the autism spectrum and programs currently available to help autistic people function better in society. The commission is considering whether the state's mental health programs, particularly in the schools, are adequate, among other things.

On Dec. 14, 2012, 20-year-old Adam Lanza opened fire at Sandy Hook Elementary School, killing 20 first graders and six educators. Lanza, who had killed his mother earlier in the day, later committed suicide.

Documents recently released by the state police show a Yale professor had diagnosed Lanza in 2006 with profound autism spectrum disorder, "with rigidity, isolation, and a lack of comprehension of ordinary social interaction and communications," while also displaying symptoms of obsessive-compulsive disorder.

Lerner said there are traits associated with autism that often explain behavior when those on the spectrum come into contact with the legal system. Those include impulsive and compulsive behavior and the inability to understand social motives and emotional situations.

A person with autism may, for example, take a neighbor at their word when told to drop by or call "any time". So when they call at 3 a.m., 3:30 a.m. and again at 4 a.m., they don't understand they are doing something wrong, he said.

"There is certainly no association between any of the features that we know about autism and the kind of planful mass murder as discussed here, that precipitated this commission," Lerner said.

Adam Lanza's father, Peter, told police that his son had Asperger's syndrome, a milder form of autism. He has indicated a willingness to share his son's school and medical records.

"We're going back and forth now trying to come up with some of the parameters about what his involvement might entail," Scott Jackson, the chairman of the commission, said Friday. "I know the commission really doesn't have any interest in having him come here and present to us. That's not what we're looking for. What we are looking for are the documents that start to tell the more complete story of Adam Lanza and his life."

Jackson hopes to report back to the commission on his progress at next Friday's meeting.

Jackson said that autism is a very personal for him. He grew up with a severely autistic brother, and that experience shaped his decision to go into public service, he said.

"This is my lived experience," he said. "There was concern within the advocacy community about tying developmental disabilities to this great tragedy. I want to say very clearly that is not the intention. This is an issue that needs to be discussed. It deserves to be discussed in public."

The commission expects to present its recommendations around the end of March.