NEW YORK: Newtown gunman Adam Lanza wore yellow ear plugs that deadened screams of his victims and ducked into a classroom to shoot himself in the mouth after one of America´s worst school massacres.

Disturbing details about last year´s mass shooting were revealed Friday when US police released thousands of pages of documents, photographs and recordings from their investigation.

The troubled 20-year-old shot dead 20 first grade children and six adults at the Sandy Hook Elementary, using a rifle taken from his suburban mother´s legally acquired home arsenal.

He was dressed almost entirely in black, his clothes -- a shirt, T-shirt, cargo pants, boxers, socks, sneakers, belt and fingerless gloves -- found spattered with blood and gunpowder after the murders.

"Two law enforcement officers arrived during the shooting, at which time the suspect ducked into a classroom and shot himself," according to an FBI incident report contained in the file.

Lanza killed himself by shooting himself in the mouth, shattering his brain and skull, according to the attached forensics report.

The documents are the latest pieces of chilling evidence that expose some of the horror that Lanza´s victims endured on December 14, 2012 in the sleepy Connecticut town.

Earlier this month, US authorities released recordings of emergency calls made by trapped and terrified people from within Sandy Hook Elementary School as the killer stalked the classrooms.

Lanza took less than 11 minutes to carry out his crime. The massacre was just the latest in a series of deadly shooting sprees across the country, and inspired a short-lived and ultimately failed drive to tighten US gun ownership rules.

The investigation was unable to find a motive other than conclude that the killer was obsessed with mass murders and had "significant mental health issues".

Lanza shot dead his mother in her bed, then drove to the school. He killed the principal and a school psychologist in the hallway, then entered two first-grade classrooms, killing two adults in each room, 15 children in one classroom and five in the other.

The weapons he used for the killings and a large number of firearms found in his home were all bought legally by his mother.

SOURCE: AFP