UPDATE: Michigan teen charged in Oxford High School shooting

A 15-year-old boy was charged Wednesday with murder, terrorism and other crimes for a shooting that killed four fellow students and injured others at a Michigan high school.

Oakland County prosecutor Karen McDonald did not reveal a possible motive for Tuesday’s violence at Oxford High School and declined to comment when pressed about whether she believed the victims were specifically targeted. But she said the shooting was premediated, based in part on a "mountain of digital evidence" collected by police.

Ethan Crumbley is accused of firing a semi-automatic handgun in a school hallway, roughly 30 miles (50 kilometers) north of Detroit. At least seven other people were injured.

Crumbley was charged with murder, attempted murder and terrorism causing death. It wasn’t immediately known if he had an attorney who could comment.

The shooting should be a wakeup call for new gun laws in a country that has become "desensitized to school shootings," McDonald told reporters.

"We have to do better," McDonald said without offering specific changes. "How many times does this have to happen? How many times?"

The charges were announced a few hours after investigators reported that a fourth student had died.

"What about all the children who ran, screaming, hiding under desks? … Those are victims, too, and so are their families and so is the community. The charge of terrorism reflects that," the prosecutor said.

Deputies rushed to the school around lunchtime Tuesday and arrested Crumbley in a hallway within minutes of the shooting. His father bought the 9 mm Sig Sauer gun last week, according to the Oakland County sheriff.

McDonald strongly suggested that more charges will be filed.

"We are considering charges against both parents and we will be making a decision swiftly," she said.

"Owning a gun means securing it properly and locking it and keeping the ammunition separate," she said.

The four students who were killed were identified as 16-year-old Tate Myre, 14-year-old Hana St. Juliana, 17-year-old Madisyn Baldwin and 17-year-old Justin Shilling.

After the attack, authorities learned of social media posts about threats of a shooting at the roughly 1,700-student school. The sheriff stressed how crucial it is for such tips to be sent to authorities, while also cautioning against spreading social media rumors before a full investigation.

Undersheriff Mike McCabe downplayed the significance of a situation in early November when a deer’s head was thrown off the school roof, which he said was "absolutely unrelated" to the shooting. The incident prompted school administrators to post two letters to parents on the school’s website, saying they were responding to rumors of a threat against the school but had found none.

Sheriff Mike Bouchard said Crumbley had no previous run-ins with his department, and he was not aware of any disciplinary history at school.

"That’s part of our investigation to determine what happened prior to this event and if some signs were missed, how were they missed and why," he said.

Isabel Flores, a 15-year-old ninth grader, told Detroit television station WJBK that she and other students heard gunshots and saw another student bleeding from the face. They then ran from the area through the rear of the school, she said.

A concerned parent, Robin Redding, said her son, 12th-grader Treshan Bryant, stayed home Tuesday after hearing threats of a possible shooting.

"This couldn’t be just random," she said.

Bryant said he had heard vague threats "for a long time now" about plans for a shooting.

At a vigil Tuesday night at LakePoint Community Church, Leeann Dersa choked back tears as she hugged friends and neighbors. Dersa has lived nearly all of her 73 years in Oxford. Her grandchildren attended the high school.

"Scared us all something terrible. It’s awful," Dersa said of the shooting.

Pastor Jesse Holt said news of the shooting flooded in to him and his wife, including texts from some of the 20 to 25 students who are among the 400-member congregation.

"Some were very scared, hiding under their desks and texting us, ‘We’re safe, we’re OK. We heard gunshots, but we’re OK.’ They were trying to calm us, at least that’s how it felt," he said.