Hundreds of police officers were scouring the Brown University campus along with nearby neighborhoods and poring over video in the hunt for a shooter who opened fire in a classroom, killing two people and wounding nine others.

The search stretched late into the night, well after the shooting erupted Saturday afternoon in the engineering building of the Ivy League school in Providence, Rhode Island, during final exams.

Surveillance video released by police shows the suspect, dressed in black, calmly walking away from the scene. His face is not visible and investigators said it wasn't clear whether the suspect is a student.

The suspect was last seen leaving the engineering building and some witnesses told police the suspect, who could be in his 30s, may have been wearing a camouflage mask, Providence Police Deputy Chief Timothy O’Hara said.

University President Christina Paxson said she was told 10 people who were shot were students. Another person was injured by fragments from the shooting but it was not clear if the victim was a student, she said.

The search for the shooter paralyzed the campus, the nearby neighborhoods filled with stately brick homes and the downtown in Rhode Island's capital city. Streets normally bustling with activity on weekends were eerily quiet.

Students sheltered in place for hours into the night. Officers in tactical gear led students out of some campus buildings and into a fitness center where they waited. Others arrived at the shelter on buses without jackets or any belongings.