Students at both Barnard College and nearby Columbia University were on edge Thursday in the wake of the murder of Barnard freshman Tessa Majors inside Morningside Park.

“It’s just so shocking that it happened so close to campus,” said Camila Vicioso, a 20-year-old Columbia freshman. “She was just walking in Morningside Park, not even that late. It’s crazy. It’s scary.”

Majors, 18, was fatally knifed in the face, neck and arm near a flight of stairs inside the Upper Manhattan park around 5:35 p.m. Wednesday, in what police sources have called a robbery gone awry.

Investigators are grilling “persons of interest” in the slaying, and exploring whether it was connected to a recent string of muggings in the area.

There had already been an increased police presence in the area, NYPD Commissioner Dermot Shea said Thursday, in vowing an “all hands on deck” response.

But some students were skeptical.

“The increased amount of police on campus and the area doesn’t seem to be keeping anyone safe,” said Mia Greenberg, a 20-year-old anthropology major at Barnard.

“It’s scary. It’s sad,” said Greenberg, who took a large environmental science class with Majors, but didn’t know her personally. “She was 18, that’s so f–ked up.”

Barnard comparative literature senior Stella Sapington, 21, said students were shaken by the murder.

“It’s jarring,” she said. “Everyone is talking about it, even on the sidewalks you can hear people talking about it.

“It wasn’t even that late,” Sapington added. “I run around there, by those stairs.

“Pretty much everyone I know has walked through the park.”