Twenty-year-old Adam Lanza fatally shot 20 first-graders and six educators at Sandy Hook Elementary School on Dec. 14 before killing himself. He also killed his mother at their Newtown home before going to the school.
An official close to the investigation said Tuesday that toxicology tests on Lanza were negative for alcohol, drugs and medication. The official, who was not authorized to publicly disclose the information and spoke on condition of anonymity, also says some victims' families were notified of the test results.
The toxicology results were first reported by The Hartford Courant.
Authorities haven't revealed whether Lanza had been prescribed medications and haven't suggested a possible motive for the massacre.
