FARMINGTON, N.M.>> The gunman who killed three people and wounded six others as he fired randomly while roaming his northwestern New Mexico neighborhood was a local high school student and his victims include a 97-year-old woman and her daughter, police said Tuesday.

Investigators were still trying to determine a motive for the attack by Beau Wilson, 18, in the Farmington neighborhood where he lived. They say he opened fire Monday, killing Gwendolyn Schofield, her 73-year-old daughter, Melody Ivie, and 79-year-old Shirley Voita.

Witnesses and police say Wilson walked through the neighborhood a short drive from downtown Farmington spraying bullets until police arrived within minutes and fatally shot him. Two police officers were among the wounded.

“The amount of violence and brutality that these people faced is unconscionable to me,” Deputy Police Chief Kyle Dowdy said. “I don’t care what age you are, I don’t care what else is going on in your life, to kill three innocent elderly women that were just absolutely in no position to defend themselves is always going to be a tragedy.”

Deputy Police Chief Baric Crum said Wilson was indiscriminately shooting at vehicles, but that some rounds also hit homes.

Dowdy said investigators do not believe Wilson knew anyone he shot.

“We’ve discovered nothing that leads us to believe that the suspect knew” the victims, he said. “We’re pretty confident in that this was completely random.”

In November, after he turned 18, Wilson legally purchased at least one gun used Monday, police said. He carried three firearms in the attack, including an assault-style weapon.

Four officers fired a total of 16 rounds at Wilson, including one of the wounded officers, said San Juan County Sheriff Shane Ferrari.

Mayor Nate Duckett said Tuesday that the Farmington officer and state police officer were treated for their wounds and released from a hospital.

Authorities began receiving reports of gunshots at 10:57 a.m. and the first officer arrived at 11:02 a.m., Police Chief Steve Hebbe said Monday in a video statement. Three minutes later, the gunman had been killed.

Joseph Robledo, a 32-year-old tree trimmer, said he rushed home after learning that his wife, Jolene, and their year-old daughter had sought shelter in the laundry room when gunshots rang out. A bullet went through his daughter’s window, without hitting anyone.

Jolene Robledo said they had just finished breakfast when she heard “pop, pop, pop, pop,” which she first thought was a car backfiring.

She said they were going to run out the back door until she heard a man curse right outside, so she quietly shut the door and hid with her daughter between the washing machine and dryer.

“I mean it was crazy. I called my husband and he could hear the gunshots over the phone,” she said. “He was freaking out and I was like, ‘don’t hang up, don’t hang up!’ ”

Joseph Robledo said he jumped a fence to get in through the back door. Out front, he found an older woman in the street who had been wounded while driving by. She appeared to have fallen out of her car, which kept rolling without her, he said.