Newtown shooting: type of weapons used by gunman Adam Lanza

Adam Lanza, the young man who killed 27 people in a massacre at Sandy Hook elementary school in Newtown, Connecticut, owned an arsenal of weapons and ammunition, court papers show.

Hundreds of rounds of ammunition and certificates from the National Rifle Association were among the items found in a search of Adam Lanza’s home.

Details of the searches were publicized after a court seal lapsed on Wednesday.

Adam Lanza, 20, first shot his mother, before killing 26 people at Sandy Hook elementary school in December 2012.

The mass shooting – which ended when Adam Lanza shot himself – shocked the US and revived debate over how to curb gun violence.

In a statement accompanying the release of the search warrants, state prosecutor Stephen Sedensky said Adam Lanza had managed to shoot all his victims and kill himself within five minutes of making his way into the school.

The 20 children and six staff members were all killed with a Bushmaster .223-calibre rifle, and the gun Lanza turned on himself was a Glock 10mm handgun, Stephen Sedensky said.

Adam Lanza had another loaded handgun with him in the school and three 30-round magazines for the rifle.

One more weapon, a 12-gauge shotgun with 70 rounds, was also found in the car Adam Lanza drove to the school.

Although the description of the gunman in the search warrants suggests he was found wearing military-style clothing and a bullet-proof vest, prosecutors said on Wednesday that Adam Lanza was not wearing such a vest.

Meanwhile, in Adam Lanza’s home a bayonet, a gun safe in his bedroom and several swords were discovered by investigators, search warrants revealed.

The documents showed Adam’s mother, Nancy Lanza, had written a cheque for her son to buy a weapon and placed it in a holiday card.

Books about autism and Asberger’s syndrome, as well as a smashed computer hard drive and gaming console were among the other items they found.

Some details such as the name of a witness, telephone numbers and serial numbers were redacted from the cache of documents.

The papers were made public at the request of Connecticut Governor Dannel Malloy, who expressed concern about information that had been leaked to the press.