Connecticutt's state medical examiner has asked scientists to study the DNA of Sandy Hook Elementary School shooter Adam Lanza. 

An Indiana University professor of psychiatry says there may be little to be learned immediately.  But he says it could be very important to begin building a collection of DNA samples in such cases.

"In the long run as we have more knowledge of what genes are involved in what impulsive or abnormal behaviors, we would be able to use such a collection to advance the research and understanding of such behaviors," says Professor Alexander Nicolescu.  

But he warns that DNA is only one factor in the determination of behavior.  

 "It's basically like a very large stack of cards and different combinations," he said.  "And depending on what hand the environment holds also, you can have different outcomes."