Tufts University briefly advised students and staff to lock their doors and stay away from their windows early Sunday morning after a double stabbing at a campus frat house, the Associated Press reports.

The advisory was lifted at about 8 a.m., but the school says there will continue to be an enhanced police presence on campus.

According to a statement by university spokesperson Kim Thurler, the attack took place at the school’s Delta Tau Delta house and “appears to be non-random.” Thurler said the victims, who are not affiliated with Tufts, were taken to a local hospital.

Authorities told The Boston Globe that the victims knew their attacker, who was still at large as of Sunday morning.

[Image via AP Images]