CNN —  

An 18-year-old student at Barnard College was stabbed to death just blocks from the school in Manhattan in an armed robbery on Wednesday, Barnard College President Sian Leah Beilock said.

There have been no arrests, but “a couple” of people are being questioned by police, NYPD Chief of Patrol Services Rodney Harrison said, stressing the investigation is still in its early stages. Those being questioned are minors, he said.

The student, freshman Tessa Rane Majors, was walking through Morningside Park at 116th Street and Morningside Drive on Wednesday evening when police believe she was confronted by between one and three individuals, Harrison said. A struggle ensued and one of the individuals stabbed Majors with a knife several times.

She staggered her way up to the “surface side” of Morningside Drive, he said, adding that she was found by a school security officer who called 911. She was taken to a local hospital where she was pronounced dead.

A knife was recovered but it’s unclear if it’s connected to Majors’ murder, he said.

“I’m very confident … that we’re going to bring this individual to justice,” Harrison said.

A law enforcement official familiar with the investigation previously told CNN a witness who spoke to the NYPD said Majors was confronted by four or five men during an initial dispute in Morningside Park.

Her cell phone was found a short distance away from where she was found, but she did not have a purse or wallet on her, the source said.

Majors is believed to be a victim of one of two robbery patterns in the area, the source said.

A pattern of crimes and the police response

Police officials and de Blasio faced questions Thursday about crimes in and around the park. The NYPD had identified issues and implemented strategies to combat the problem, Harrison said. The department increased patrols in and around the park and the nearby schools, including Barnard.

“The idea that a college freshman at Barnard was murdered in cold blood is absolutely not only painful to me as a parent, it’s terrifying to think that that could happen anywhere,” de Blasio said at the news conference.

“It’s unbelievable to me that that could happen here, next to one of our great college campuses,” he added. “It’s an unacceptable reality.”

The city has offered Barnard College any help it needs, and it’s sending mental health professionals to help students deal with the news, de Blasio said.

“This is an unthinkable tragedy that has shaken us to our core. Please know that we are all grieving together and I am thinking of you as we process this awful news as a community,” Barnard College President Sian Leah Beilock said, adding that Barnard’s public safety department provides a 24-hour escort service for students.

The was a substantial decrease in major crimes in Morningside Heights over the past three decades, according to crime stats from the NYPD.

The precinct has recorded a 48.5% decrease in major crimes between 1998-2018 and a 79.8% change from 1990-2018. For the 2019 calendar year, the precinct reported 17 robberies in and around Morningside Park.

’A personality no one could ever copy’

Majors was from Charlottesville, Virginia, and previously lived in neighboring Waynesboro.

“She was one of the sweetest people I know. She had a kind heart,” Lydia Pickering told CNN. As kids, she and Majors lived two houses down from one another in Waynesboro, Pickering said. Majors was like an older sister, she told CNN.

“I can’t even begin to explain the impact she had on me,” Pickering said. “She brought joy wherever she went. She had a personality no one could ever copy, she was really just special.”

Majors and was well known on the local music scene, said Jeyon Falsini, assistant manager of The Southern Café and Music Hall, one of the venues where she performed. Majors had scheduled two gigs in the Charlottesville area during January, he said.

“She was committed to music. It was her art form,” he said.

Lexi Phelan, who met Majors this year at Barnard, shared two classes with her.

“She was excited about life and deeply devoted to her music. She came to class always excited about a performance or a new technique she learned, whether it be for a modern alternative rock song or a classical guitar piece,” Phelan said.

Barnard College is an all-women’s school in Manhattan with more than 2,600 students. The school’s campus stretches from West 116th Street to West 120th Street off Broadway in the Morningside Heights neighborhood of New York City.

“The close-knit community at Barnard College is in shock right now,” de Blasio said in a tweet. “We’ve lost a young woman full of potential in a senseless act of violence. I want every student and every member of faculty to know your city will be with you in the days ahead.”

CNN’s Taylor Romine, Mirna Alsharif and Eric Levenson contributed to this report.