A Brown University senior said he spent the night helping evacuate classmates after losing a close friend in a shooting at his school that left two people dead and nine others injured.

Ben Marcus told “Fox & Friends Weekend” on Sunday that he was celebrating Shabbat at Brown’s Hillel, a center for Jewish life on campus, when the building’s security guard rushed in with an urgent warning.

“None of us were on our phones. The security guard at the Hillel building just leaped into action, and he said, ‘Everyone upstairs, this is really serious. There’s a shooter,'” Marcus said.

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He described sheltering with about 30 students for nearly seven hours and praised staff at both the Hillel and the university for keeping students safe and informed.

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Still, students are scared and confused as they navigate the aftermath of the tragedy that halted final exams.

“There were finals yesterday, there were finals all week, and students are just terrified,” Marcus said.

One of the victims, whose name has not yet been released, was a close friend of Marcus.

“I actually lost a very good friend of mine… I don’t think her name is public yet,” he said. But she was a really, really special person… really amazing at creating dialogue and interfaith activities, and we’ll really miss her.”

Marcus also noted how easy it is to enter some buildings on campus. He said most remain unlocked during class hours, “and even when the building is supposed to be locked — the engineering building in particular — it’s pretty common for it to be propped open with a chair.”

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Police said Sunday that a person of interest is in custody following the deadly shooting. Police told Fox News that the individual was found at a hotel in Coventry, which is about 17 miles south of Providence. 

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Providence Chief of Police Colonel Oscar L. Perez Jr. declined to say whether the person was affiliated with Brown University when asked by reporters at a news conference, citing the early stages of the investigation.

Former Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) special agent Bernard Zapor discussed the latest on the investigation during “Fox & Friends Weekend,” warning that the shooter operated without “conscience” when he decided to open fire at the school. 

“Make no mistake,” he said. “Somebody that goes in and makes a decision to take human life on a mass scale, or any scale, is really operating without conscience. And so the normal things that we’re expecting from a human being don’t exist.”

Fox News’ Ashley Carnahan and Bryan Llenas contributed to this report.