A 15-year-old opened fire at his Michigan high school Tuesday, killing at least three people and wounding eight others, authorities said, in what appears to be the deadliest episode of on-campus violence in more than 18 months.

The suspect, who police have not named, was a sophomore at Oxford High School in southeast Michigan and had attended class before the rampage, Oakland County Undersheriff Mike McCabe said. The teen is on suicide watch and is not talking to authorities, leaving his motives unclear, officials said late Tuesday night.

Authorities identified the students who were killed as 14-year-old Hana St. Juliana, 16-year-old Tate Myre and 17-year-old Madisyn Baldwin.

Here are some significant developments

  • Three more students, two girls and a boy, were in critical condition Tuesday evening. Another was in serious condition, three others were stable and a 47-year-old teacher was released from the hospital.
  • The semiautomatic handgun the suspect allegedly used was purchased by his father four days before, authorities said.
  • School administrators said earlier this month that they investigated and debunked rumors swirling about threats to campus safety. McCabe said authorities were not aware of warning signs, urging caution toward claims on social media.
  • Several leaders, including President Biden and Rep. Elissa Slotkin (D), who represents the district where the high school is located, expressed sadness and outrage.