LAS VEGAS (AP) — A defense attorney raised doubt Tuesday about the competency of a 16-year-old student to face sex assault and attempted murder charges in a violent after-school attack that left a Las Vegas high school teacher injured and unconscious in her classroom last week.

In a police report, investigators said the boy’s mother said he had no known medical or mental disabilities but recently seemed “depressed and disconnected.”

A local judge confirmed with the teen’s lawyer and a prosecutor that state law calls for him to be prosecuted as an adult if the case moves forward on those charges and others including first-degree kidnapping, which could put him in prison for the rest of his life.

Defense attorney Paul Adras told Justice of the Peace Joe M. Bonaventure he’ll seek a mental evaluation for his client ahead of a May 6 competency hearing in state court.

The Associated Press is not naming the teen, pending a competency determination. He is being held as an adult on $500,000 bail at the Clark County Detention Center in Las Vegas.

Additional charges including more counts of sexual assault and battery by strangulation were added Monday, bringing to 15 the number of felonies he faces. He has not been asked to enter a plea.

A Las Vegas police arrest report obtained Tuesday provided new details of the alleged attack at Eldorado High School. It said the student, a junior, went to the teacher’s classroom last Thursday afternoon to talk about his grades.

The female teacher told investigators the teen is physically larger than her, approached her as she sat at her desk and choked her from behind with a rope or cord before pulling a bookcase and filing cabinet down upon her.

The teacher “asked … repeatedly why he was ‘doing this’ to her,” before she lost consciousness, police said. She “recalled (him) telling her he had something like ‘multiple personalities,’ and … he ‘didn’t like teachers’ and was ‘getting revenge.’ “

The teacher said she tried to fight her attacker and scratched his arms. When she awoke, she had blood in her hair and her clothes were disheveled.

“I don’t know why I attacked her, she was good to me,” the arrest report quotes the student telling detectives. It said he admitted taking the teacher’s keys before he fled the campus.

He attends ROTC and was with his mother driving him back to school about two hours later for an award ceremony when they were stopped and he was arrested by school police.

His mother described her son as a good student who was “not diagnosed with any medical or mental disabilities.” She told police that in recent months he seemed “depressed and disconnected” but would not talk about what was wrong.

Officials said the teacher was hospitalized. Neither her name or the extent of her injuries were immediately made public. The police report said the teen described removing her clothes, and said DNA evidence was collected.

Outside court, Adras called it too early in the case to comment on his client’s behalf, and acknowledged intense public interest since his arrest.

“I know there’s a lot of information going out on social media,” the attorney told The Associated Press. “We’re asking everyone to respect the process.”

Adras added that prosecutor Lindsey Moors informed him the case may be presented to a grand jury behind closed doors.

Clark County District Attorney Steve Wolfson, outside court, expressed frustration with escalating violence in Clark County schools, the nation’s fifth-largest district, and told reporters that he spoke Tuesday with school Superintendent Jesus Jara.

“This is an example of the kind of behavior that will not be tolerated,” Wolfson said of the allegations against the teen.

Wolfson, Jara and other officials convened a news conference two weeks ago to call for calm in the sprawling school district, which has more than 300,000 students and 18,000 teachers at about 336 campuses. Wolfson, the top prosecutor in Las Vegas since 2012, is running for reelection this year.

Jara blamed incidents on the “stress, anxieties and isolation of the (coronavirus) pandemic.”

The same day the news conference was held, a campus police officer fired three gunshots at a moving car that had struck a girl amid a report of an after-school fight in a parking lot at a downtown Las Vegas high school. Among four teenage non-students in the car, the driver and a passenger received minor wounds, authorities said. The girl struck by the car was not seriously hurt.

Classrooms are empty this week during spring break.

Since schools opened in August, campus police have reported 3,000 assaults and fights, and confiscated more than 25 guns. Brawls at some schools have involved non-students, adults and parents. The mothers of two students have been accused in separate cases of using their vehicles as weapons to defend their children from schoolmates.