NEWTOWN, Conn. - Officials say that gunman Adam Lanza tried to buy a gun on Tuesday.

He was denied the gun from Dick's Sporting Goods. Officials say they are contacting other local stores and gun ranges to see if Lanza tried to purchase at other locations.

Police believe that 20-year-old Lanza killed 20 children and six adults before turning the gun on himself at Sandy Hook Elementary School.

So far, authorities have not spoken publicly of any possible motive.

They found no note or manifesto, and Lanza had no criminal history.

Witnesses said the shooter didn't utter a word. Sandy Hook Elementary School will remain a crime scene until tomorrow.