NEWTOWN, Conn. – As a teenager, Adam Lanza would come in for a haircut about every six weeks without speaking or looking at anyone and always accompanied by his mother, said stylists at a salon in the town where Lanza gunned down 27 people last week, including his mother, before killing himself.

He stopped coming in a few years ago, and the employees at the salon thought he had moved away, said stylist Bob Skuba.

The comments from him and his colleagues were among the first describing how the Lanzas interacted with each other. Investigators have found no letters or diaries that could explain the attack, one of the deadliest mass shootings in U.S. history.