Updated

A New Haven attorney is asking permission to sue the state for $100 million on behalf of a student who survived the mass shooting at Sandy Hook Elementary School in Newtown, Connecticut.

The Hartford Courant reports that attorney Irving Pinsky filed notice Thursday with Claims Commissioner J. Paul Vance Jr. The state has immunity against most lawsuits unless permission to sue is granted.

On the morning of Dec. 14, Adam Lanza shot his mother, Nancy Lanza, four times in the head, authorities said.

He then drove to the elementary school in her car with four guns, including a shotgun that was left in the back of the vehicle, and shot up two classrooms killing 20 students and six adults around 9:30 a.m., police say. Police added that multiple 30-round magazines and hundreds of bullets were also found at the scene.

The rifle used was a Bushmaster .223-caliber, according to an official with knowledge of the investigation who was not authorized to speak about it and talked on condition of anonymity. The gun is commonly seen at competitions and was the type used in the 2002 sniper killings in the Washington, D.C., area. Also found in the school were two handguns, a Glock 10 mm and a Sig Sauer 9 mm.

Pinsky said the 6-year-old student, identified as "Jill Doe," was in her classroom when "the horrific confrontation" with Lanza came over the loudspeaker. "She was in her classroom, and over the loudspeaker came the horrific confrontation between the fellow who shot everybody and other people," Pinsky told the Hartford Courant. "Her friends were killed. That's pretty traumatic."

A custodian ran through the halls, warning of a gunman on the loose, and someone switched on the intercom, alerting people in the building to the attack -- and perhaps saving many lives -- by letting them hear the hysteria going on in the school office, a teacher said. Teachers locked their doors and ordered children to huddle in a corner or hide in closets as shots echoed through the building.

Pinsky said the student has been traumatized by the killings, and accused the state of failing to protect students from "foreseeable harm."

Connecticut Gov. Dannel Malloy said Lanza committed suicide when he heard first responders coming. A Connecticut official said Lanza killed himself with a single bullet to the head from the10 mm gun, and the bullet was recovered in a classroom wall.

Sandy Hook Elementary School has close to 700 students.

Newtown is in Fairfield County, about 45 miles southwest of Hartford and 60 miles northeast of New York City.

The Associated Press contributed to this report.