He pled guilty to felony charges and is being charged as an adult, CBS2's Jenna DeAngelis reported.
It was another emotional day for Majors' family members who were in court to hear that guilty plea. That's now two of the three teens allegedly involved admitting their involvement.
He then read a statement, describing what happened the night the Barnard College freshman, from Virginia, was fatally stabbed in Morningside Park.
Lewis was 14 when a schoolmate, Rashaun Weaver, asked him to "do robberies with him" and a third teen.
Lewis said he backed out twice -- then a third actual mugging failed.
On the night of Majors' murder, Lewis said, "I assumed that Rashaun had a knife on him, but I didn't see it and using a knife was not part of our plan."
Lewis said they saw the victim in the park, looking down at her phone, and that Weaver kicked her hard in the back, screaming, "Give me your money!" He added Majors then said, "Are you seriously trying to rob me?"
They tussled and both fell to the ground, Lewis said.
He described seeing a witness, and alerted his friends to leave. That's when Weaver showed Lewis that the girl had bitten him.
Lewis described seeing feathers come out of her jacket, but claimed he didn't know she had been "stabbed, let alone killed." That is, until he saw the story the next morning and realized it was her.
The third teen involved, age 13 at the time, pled guilty to robbery charges and was sentenced last year to 18 months in juvenile detention.
After the court hearing, an attorney representing Weaver, the alleged stabber who had previously pled not guilty, spoke.
"This was not a premeditated murder, as we heard inside. These are a 14- and a 13-year-old boy and we should all remember that," Jeffrey Lichtman said.
Family, including Majors' father, silently left court. In previous statements, they described her as "talented, kind and beloved" and called her absence "palpable and unrelenting."
The Majors family later released the following statement:
"We are aware of today's proceeding involving the second guilty plea. We remain resolute in our belief that all parties who bear responsibility for Tess's senseless death will be held accountable, and we are deeply grateful to the many people who continue to pursue that goal.
"In particular, we would like to thank the members of the Manhattan District Attorney's Office and the New York City Police Department for their tireless and thorough efforts. We have maintained confidence in their work from the beginning and appreciate their diligence and the compassion they have shown us."
Lewis has been accused of preventing Majors from escaping that say, but there was no mention of that from him Tuesday.
CBS2 has learned, the family will offer a victim impact statement at sentencing on Oct. 14.
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