By Susan Candiotti and Ben Brurmield
(CNN) — There has been much speculation over what was going on in Adam Lanza’s head, when he walked into Sandy Hook Elementary School in Newtown, Connecticut, with an assault rifle in December and opened fire on small children.
Thursday morning, state prosecutors are planning to release new documents in the case, but it may not shed more light on the reasons for the mass shooting.
The families of victims were briefed Wednesday about the new documents, said Stephen Sedensky, a local prosecutor.
The documents may contain some new information but maybe no big surprises, said Connecticut State Police spokesman Paul Vance.
Some of the documents to be released in the Sandy Hook case have been redacted at the prosecutor’s request, Vance said.
State police are also continuing their investigation, which is not expected to be completed until June, he said. Investigators have not yet determined what pushed Lanza over the edge, Vance said.
The shooting has lead Connecticut legislators to reexamine the state’s gun laws, which are already some of the nation’s strictest, and it reopened a national debate on gun control.
U.S. Sen. Richard Blumenthal, D-Connecticut, has announced plans to introduce legislation requiring background checks to purchase ammunition. He has put pressure on members of his state legislature to take action, in order to bolster his efforts on a national level.
On December 14, Lanza, 20, took guns belonging to his mother, Nancy, and shot her as she slept in her bed. Then he went to the school in Newtown, Connecticut, where he gunned down 20 children and six staff members before killing himself.
It was one of the worst mass shootings in U.S. history.
