Oxford High School Shooting: Oakland County prosecutor says Tuesday's shooting was planned 'well in advance'

Oakland County Prosecutor Karen McDonald announced murder and terrorism charges against Ethan Crumbley, the 15-year-old accused of shooting students at Oxford High School on Tuesday. McDonald said he would be charged as an adult and that the tragedy was premeditated. 

McDonald spoke at 2 p.m. about the case and said that she would only use his name once to retain focus on the victims and not the suspect.

Crumbley is charged with one count of terrorism, four counts of first-degree murder, seven counts of assault with intent to murder, and 12 counts of possession of a firearm while committing a felony in connection with the school shooting that killed four students and injured seven other people, including a teacher.

She also said she is considering charges against the 15-year-old's parents. The gun was purchased by his father four days before the attack.

During her update, McDonald said the suspect did not act on impulse and that he planned the shooting "well in advance." She did not elaborate further on how long the attack was planned or on a possible motivation.

RELATED: What we know about the victims of the Oxford High School shooting

"There are facts leading up to this shooting that suggests this was not just an impulsive act," McDonald said. She added that charging the teen as an adult was "necessary to achieve justice and protect the public; any other option would put all of us at risk of this person because they could be released and still a threat."

McDonald said Crumbley planned the attack based in part on a "mountain" of digital evidence, including videotape and social media posts.

"It wasn't even a close call, it was absolutely premeditated," McDonald told reporters.

Four students were killed in the mass shooting on Tuesday. Tate Myre, 16, Madisyn Baldwin, 17, 14-year-old Hana St. Juliana, and 17-year-old Justin Shilling were killed.

Shilling died around 10 a.m. on Wednesday. 

McDonald acknowledged that the terrorism charge was not "typical" but said it was applicable in this case because of the survivors who witnessed the mass shooting.

"What about the children who ran screaming and hid under desks? Those are victims too and so are their families," McDonald said. "The charge of terrorism reflects that."

Oakland County Sheriff Michael Bouchard said he "agreed 100%" with the charges filed against the suspect.

"If you weren't hit by a bullet, [it] doesn't mean you weren't terrorized that day and won't have nightmares about it the rest of your life," the sheriff said. "That had to have been an absolutely terrorizing moment in anyone's life, I don't care if you're an adult or a child."

RELATED: Fourth Oxford High School shooting victim dies

What happened at Oxford High School?

At 12:51 p.m., the first call to 911 was made from inside the school. It was the first of at least 100 alerting law enforcement to the shooting as it was unfolding inside the school.

Someone had started shooting students in the school with a 9 mm Sig Sauer. Several people were shot and Oakland County dispatchers got deputies to the scene in just a few minutes.

Two minutes after the first deputies arrived, they encountered the suspect in the hallway holding the Sig Sauer. Without a shot fired by deputies, he was taken into custody. 

But at least three students were dead. Eight others were hurt and two of them are fighting for their lives.

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Who is the Oxford High School shooter?

The 15-year-old shooter, Ethan Crumbley, has not yet been publicly identified by the sheriff's office, but was identified Wednesday afternoon by McDonald. He has retained an attorney and his parents instructed him not to speak with investigators, according to Oakland County Sheriff Michael Bouchard. 

He is in custody at Oakland County Children's Village.

The suspected shooter used a 9mm semi-automatic handgun that was purchased by his father four days before the shooting

When deputies stopped the teen, the gun still had seven rounds in it. He was arrested without incident.

"We believe he came out of a bathroom with a weapon in hand. Deputies took (the gun) from him he was walking down the hall," Oakland County Sheriff Michael Bouchard said. "That interrupted what could have led to several more victims. The way I see it is, there were seven more victims in that gun."

Investigators searched the shooter's home on East Street on Tuesday evening and seized key evidence, including what appeared to be several long guns.