(OXFORD TOWNSHIP, Mich.) — A fourth student has died following Tuesday afternoon’s shooting at a Michigan high school.

Justin Shilling, 17, died at about 10:45 a.m. Wednesday in the wake of the shooting at Oxford High School in Oxford Township, sheriff’s officials said. Three other students, ages 14 to 17, died Tuesday. Seven people, including a teacher, were injured.

The suspected gunman, 15-year-old Ethan Crumbley, was taken into custody and is being charged as an adult, Oakland County Prosecutor Karen McDonald said at a news conference Wednesday.

McDonald said she is confident prosecutors can prove the shooting was premeditated “well before the incident.”

He has been charged with one count of terrorism causing death; four counts of first-degree murder; seven counts of assault with intent to murder; and 11 counts of possession of a firearm in commission of a felony, she said. Additional charges are possible, McDonald said.

There’s no indication that the victims were specifically targeted, Oakland County Sheriff Michael Bouchard said Wednesday.

The teen allegedly took his father’s semiautomatic handgun, a 9mm Sig Sauer pistol, with him to school, officials said.

The teen allegedly came out of a bathroom and began shooting. He never went into a classroom and was apprehended in a hallway, Bouchard said.

Thirty spent shell casings have been recovered, the sheriff said. The suspect had 18 live rounds left, he said.

The suspect’s father purchased the weapon on Black Friday and officials are looking into how the family stored its guns and how much access the teen had to them, according to a source briefed on the investigation. The suspect had apparently used the gun prior to the school shooting, the source said.

McDonald said prosecutors are considering charges against both of the suspect’s parents.

The first three students killed in the Tuesday shooting were Madisyn Baldwin, 17, Tate Myre, 16, and Hana St. Juliana, 14.

Four of the seven injured victims remained in the hospital on Wednesday, the sheriff said. Among those in the hospital is a 17-year-old girl who is in critical condition with a gunshot wound to the chest, he said.

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