NEW YORK (CBSNewYork) — Just 24 hours after the fatal police shooting of an emotionally-disturbed woman in the Bronx, demonstrators were in the street demanding justice amid a heavy police presence.

The incident happened shortly after 6 p.m. Tuesday inside 66-year-old Deborah Danner’s apartment at Jaime Towers Housing at 630 Pugsley Avenue in the Castle Hills section.

Police said NYPD Sgt. Hugh Barry, who arrived at the home after receiving a call about an emotionally-disturbed person, found Danner with scissors in her hand.

“He engaged the female in conversation and persuaded her to put down the scissors,” said NYPD Assistant Chief Larry Nikunen. “The female subject approached the sergeant and grabbed a baseball bat. As she attempted to strike the sergeant, he fired two shots from his service revolver, striking her in the torso.”

A specially trained Emergency Services Unit squad was en route, but the deadly confrontation happened before they arrived, CBS2’s Magdalena Doris reported.

Danner was immediately rushed to Jacobi Hospital, but did not survive.

De Blasio called the shooting tragic and unacceptable.

“It should never have happened,” de Blasio said during a news conference Wednesday afternoon. “The NYPD’s job is to protect life.”

He promised a full investigation.

“We are determined to get to the bottom of this incident, we are determined to seek justice and we are determined to ensure that a tragedy like this never happens again in our city,” de Blasio said.

NYPD Commissioner James O’Neill said it’s clear “we failed” and that “our first obligation is to preserve life, not to take a life if it can be avoided.”

He added that as commissioner, he is committed to “get to the answers of what happened.”

“We do have policies and procedures for handling emotionally-disturbed people,” he said. “It looks like that some of those procedures were not followed.”

Danner’s sister was in the hallway as the situation unfolded and never expected to hear gunshots ring out, de Blasio said.

“I was down the hall from my sister’s apartment when I saw officers rush in and I heard three gunshots,” Jennifer Danner said.

As CBS2’s Jessica Layton reported, Jennifer was her sister’s guardian.

“I asked if they shot my sister and received no response. After she was taken to Jacobi Hospital I was informed she had passed away,” she said.

According to her family, Danner had been dealing with mental illness for decades and police had responded to similar calls in the past. Each of those times, Danner was taken away safely.

“In those other instances, the NYPD successfully removed Deborah from the apartment and they went off to the hospital,” de Blasio said. “Something went horribly wrong here.”

“Deborah Danner should be alive right now. Period,” the mayor said. “If the protocols had been followed, she would be alive. It’s as simple as that.”

As CBS2’s Hazel Sanchez reported, her cousin Wallace Cooke Jr., a former NYPD officer, said Danner was a nice woman who suffered from schizophrenia and often refused medication.

“Debbie was sick,” Cooke said. “She was in college and she was a very smart, book-wise person, and she don’t deserve to be dead.”

Neighbors also said she had a history of erratic behavior.

“The lady be hollering, screaming,” Raphelle Gundy said. “You think she’d be in there wrestling with somebody, talking very violently.”

Police said the sergeant was armed with a Taser, which was never deployed. Now, Black Lives Matter activists and members of the community want accountability.

“It’s disturbing that police do not de-escalate these situations,” said Black Lives Matter activist Hawk Newsome. “They have Tasers, they have mace. Why is it that people always end up dead?”

“It’s not about rallies, it’s about programs that need to be set in place by the NYPD,” said resident Paul Nickerson.

“I don’t why they didn’t use a Taser,” another neighbor told 1010 WINS’ Glenn Schuck. “It makes no sense.”

In a statement, Bronx Borough President Ruben Diaz Jr. condemned the shooting.

“This elderly woman was known to the police department, yet the officer involved in this shooting failed to use discretion to either talk her down from her episode or, barring that, to use his stun gun,” Diaz said. “That is totally unacceptable.”

Public Advocate Letitia James said she was also “deeply concerned.”

“I am calling for a swift and thorough investigation into this tragic incident and for the findings to be released publicly,” James said in a statement. “While we are still learning details about this evening’s incident, I am renewing my call to expand the use of non-lethal use of force by the NYPD.”

The Rev. Al Sharpton called the shooting “atrocious.”

“The need for an overhaul in police training and a review of those qualified to become police officers is apparent and must be dealt with,” Sharpton said. “O’Neill’s statements were good and responsible but should be the beginning of the overhaul and systemic change, not the conclusion of this case.”

Barry had participated in a new training regiment that includes de-escalation, de Blasio said.

“We need to know why this officer did not follow his training and did not follow those protocols,” de Blasio said. “There were obviously other options here.”

O’Neill said one of the things officials will be looking at is why the sergeant didn’t use his Taser, 1010 WINS’ Al Jones reported.

“It’s not enough to say that the vast majority of cases, we get it right, because any one life lost is a precious life,” he said.

Barry was taken to the hospital for an evaluation, which standard after a shooting, and has been placed on modified duty. He is an eight-year veteran of the NYPD with no prior shooting incidents.

Attorney General Eric Schneiderman’s office says it is “reviewing the incident to determine whether or not it falls within the attorney general’s jurisdiction under the executive order. We extend our deepest condolences to Ms. Danner’s family.”

Last year, the NYPD dealt with 150,000 calls about emotionally disturbed people. O’Neill said while there are detailed plans in place for responding, “If we need to change the way we do business, we’ll do that.”

Tuesday’s shooting evoked memories of the 1984 police killing of 66-year-old Eleanor Bumpurs. The Bronx woman was fatally shot by police as she waved a knife at officers evicting her from her public housing apartment after falling behind in her rent.