NYPD divers were probing a pond inside Morningside Park Saturday for new evidence in the fatal stabbing of Barnard College freshman Tessa Majors.

Investigators closed a portion of the park while the search was underway, and at least one diver was in the water, cops at the scene told The Post.

Morningside Pond is just a few blocks south from the park steps where Majors, 18, was killed Wednesday night during a robbery-gone-wrong that left her with stab wounds to the neck and arm, police said.

She was discovered by a school security guard at the top of the steps near West 116th St. and Morningside Dr. at about 5:30 p.m. and rushed to Mount Sinai St. Luke’s Hospital, where she died.

Her cell phone was recovered nearby, which allowed investigators to identify her.

Two middle-schoolers were busted Friday for the group attack, police sources told The Post. One of the teens, 13-year-old Zyairr Davis, confessed to involvement in the attempted robbery, telling police that he and two middle school friends spotted Majors, a musician and Virginia native, and snuck up behind her, sources said.

“He said they tried to rob her. Then she was stabbed, and she died,’’ a source said. “They were trying to rob her, she resisted, and they stabbed her.’’

It was not clear what the divers were looking for—though Majors’ bag was not on her when cops found her body, sources said.

A third suspect was still being sought Saturday.