Europe 1 with AFP 9:36 p.m., December 01, 2021

A student caught in the shooting at a high school in the northern United States on Tuesday succumbed to his injuries, increasing the death toll to 4.

Six injured students remained hospitalized Wednesday while the teacher, slightly injured in the shoulder, left the hospital on Tuesday.

A student injured Tuesday in the shooting at a high school in the northern United States succumbed to his injuries, bringing the death toll to four, local police said on Wednesday, still trying to explain the shooter's motives.

A fourth victim, aged 17

"We are saddened to report that a fourth victim has succumbed to his injuries," Oakland County Sheriff's Department said on their Facebook page.

Justin Shilling, 17, died in hospital at around 10:45 a.m. local time (3:45 p.m. GMT), Sheriff Michael Bouchard told AFP.

The day before, a 15-year-old high school student in Oxford, a suburb of Detroit in Michigan, had shot dead three high school students aged 14 to 17 and injured eight people including a teacher.

Six injured students remained hospitalized Wednesday while the teacher, slightly injured in the shoulder, left the hospital on Tuesday.

The student, whose identity has not been made public, used a Sig Sauer SP 2022 9mm semi-automatic pistol, purchased by his father on Friday, the day of the big Black Friday promotions, according to police.

"He clearly came to kill people," Sheriff Bouchard said on CNN Wednesday, noting that he had fired at least 30 bullets.

The shooter in custody

"He would shoot people at point blank range, often aiming at the head or chest," he added.

The gunman went to the police inside the school itself and was taken into custody.

He remained silent on the motives for his gesture, his parents having asked him not to speak to the police, according to the authorities.

Oakland County Prosecutor Karen McDonald is due to announce at 2:00 p.m. local time (7:00 p.m. GMT) the young gunman's indictment on Wednesday, according to her services.

Massive shootings remain a recurring scourge in the United States, where the right to own guns is constitutionally guaranteed.