(MCT) — HARTFORD, Conn.—After a week of intensive investigation following the slaughter of 20 first-graders and six women at an elementary school in Newtown, normally promising lines of inquiry have turned up little if anything to shed light on what motivated Adam Lanza, the reclusive, 20-year old gunman, to kill.

A preliminary examination of his cellular telephone showed that he had made or received few, if any calls, investigators and others familiar with the matter said. No information has yet emerged from investigators on any possible text messages he may have sent or received.