Those were the words spoken by Tessa Majors, 18, in the last moments of her life, as she bled to death during a robbery near Barnard College, police said. Majors, a student at the college, was found lying face down just outside Morningside Park in December and had multiple stab wounds, including one to her heart, police said.

On Saturday, almost two months after Majors’ killing, authorities arrested Rashaun Weaver, 14, who will be tried as an adult, on two counts of second-degree murder and several counts of robbery. Police said Saturday that Weaver had fatally stabbed Majors.

“Sadly, it cannot bring back this young woman, this student, this victim,” Dermot F. Shea, the New York Police commissioner, said at a news conference Saturday. “We can say we are confident that we have the person in custody who stabbed her.”

Majors’ killing shocked the city, given that violent crime had fallen in recent years, although residents of the neighborhood had been concerned about the safety of the area around Morningside Park.

After police began to suspect three African American boys, aged 13 to 14, of being involved in robbing and fatally stabbing Majors in a Manhattan park, echoes of the Central Park Five case — which involved teenagers wrongly convicted of the rape of a jogger in 1989 — soon loomed over the investigation.

A day after the attack, police detained one of the boys, a 13-year-old, who implicated himself, Weaver and another 14-year-old middle school classmate in the robbery. The 13-year-old was arrested and charged with second-degree felony murder as a juvenile.

But it would take weeks for the police to build their case against Weaver.

Here is what we know about how the case was built:

Q: What do we know about the 14-year-old’s involvement in the murder?

A: To tie Weaver to the killing, authorities said investigators had collected several pieces of physical evidence, including blood samples and a cellphone.

The DNA recovered from one of Tessa Majors’ fingernail clippings matches the DNA profile of Weaver, according to a criminal complaint.

Police also accumulated video evidence, witness identification and Weaver’s own statements.

Early in the investigation, police identified Weaver as the person they believed stabbed Majors after she bit his hand during a violent struggle with the three assailants. In an audio recording of a conversation obtained by police and detailed in the complaint, Weaver said that he stabbed Majors with a knife because “she was hanging on to her phone.”

Investigators also reviewed video footage that showed that the boys initially appeared to have targeted a man in the park before switching their attention to Majors. Police said they had recognized Weaver because he had been wearing the same jacket he wore in another armed robbery that they had suspected him of committing days earlier.

The police commissioner said Weaver was arrested without incident at 10:30 p.m. Eastern time Friday in the lobby of a building in Harlem in the presence of his mother and other relatives.

Weaver’s lawyer, Elsie Chandler, declined to comment.

Q: Why did the police wait almost two months to arrest him?

A: Police seemed to make a huge break in the case when the 13-year-old in the group implicated Weaver during his interview with investigators. But officers could not find Weaver to question him.

He appeared to have gone into hiding in the days after the murder. Police took the unusual step of releasing a photo of Weaver and asking the public’s help in obtaining information leading to his arrest.

Then, in late December, police tracked the teenager to a family member’s home in the Bronx.

Authorities said they believed that his family was protecting him until an injury on his hand healed. An official briefed on the investigation described the wound as consistent with a bite. Though police detained Weaver for questioning, he was eventually let go without being charged.

Investigators soon began to focus on DNA evidence in order to tie Weaver to the killing. Eventually that evidence led to Weaver’s arrest Friday.

He appeared briefly in court Saturday and was sent without bail to a juvenile facility.

Police have interviewed a third suspect, another 14-year-old, but so far have not charged him.

Q: Why is he being charged as an adult?

A: Last year, New York fully put into effect a law that raised the age of criminal responsibility to 18 years old after having for years processed 16- and 17-year-olds as adults. The law, known as Raise the Age, meant that 16- and 17-year-olds arrested and charged with nonviolent crimes would have their cases heard in family court and would receive “intervention and evidence-based treatment.”

In the case of teenagers who are under 16, prosecutors have discretion to try them as adults in some cases of violent crimes.

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The 13-year-old boy who was arrested days after Majors’ killing and charged with second-degree felony murder will be tried as a juvenile. He is accused of taking part in the robbery, not of stabbing Majors, and is expected to face trial in family court in March.

But Weaver will be charged in the youth court division of criminal court, where judges have some training in family court procedures. He faces two counts of murder: one count of intentional murder and one of felony murder — a murder that occurs during another crime, in this case the robbery.

“The law requires that a 13-year-old who is charged with felony murder be prosecuted in family court,” said Danny Frost, a spokesman for Cyrus R. Vance Jr., the Manhattan district attorney. “The law gives jurisdiction to our office when a 14-year-old is charged with intentional murder and felony murder, which is why the case is in criminal court.”

At a news conference Saturday, Vance recognized the significance of dealing with a 14-year-old. “We will be very careful to safeguard all the rights that he has as we go forward with this case,” he told reporters. “We are committing to fairness because only a fair process will result in true justice for Tessa Majors.”

This article originally appeared in The New York Times .