His ailments had started to make caring for him difficult in a setting not intended to provide round-the-clock medical help; the Hughes House has a full-time nurse, a part-time psychiatrist and other staff members. The building is noted in Police Department records as having a history of calls for emotionally disturbed people.
Urban Pathways had begun discussing Mr. Lockhart’s long-term health and living plan.
“He was going to eventually lose his vision,” Mr. Shack said.
On Monday, there were apparently few signs preceding Mr. Lockhart’s attack.
“He seemed to be fairly calm and no agitation,” Mr. Shack said. “But it’s still early. We are still interviewing the people who encountered him.”
A police official said Mr. Lockhart, a first-floor resident, had a conversation with the two female security guards before stabbing one in the left arm and the other in the chest and arm. It was not clear what they spoke about, but the investigation into the stabbing was continuing, a process that would include interviewing the guards and witnesses.
Some people helped the guards while others called 911, reporting an assault in progress, and uniformed officers from the 48th Precinct arrived soon after, the police said.
The Emergency Service Unit, whose officers are specially trained to handle emotionally disturbed people, would not immediately have been called to the scene of an assault, the police said. The police said the incident was not reported as involving an emotionally disturbed person.
Within roughly a minute of the two officers arriving and walking into the lobby, they shot Mr. Lockhart multiple times, the police official said. The police said Mr. Lockhart refused more than 20 commands from officers to drop the knife and then stepped toward officers. The department has not released the officers’ names.
The officers did not have Taser stun guns. The Police Department has provided more officers with the stun guns recently as alternatives to firearms, though they do not always work in subduing people and civil rights lawyers worry that officers use them even when they face little danger.
More than 13,600 of the Police Department’s 36,000 uniformed officers are now trained to use Tasers, up from nearly 10,000 last year, the department said on Tuesday. In all, more than 2,300 Tasers are in circulation, up from 1,710 last year.
Had the situation turned into a lengthier standoff, there may have been a Taser on the scene; a sergeant, who would typically carry a Taser, arrived just as the officers were firing.
The officers were wearing body cameras. But the Police Department said investigators were still reviewing the footage and consulting with prosecutors before they made a decision about whether to release any part of it. The decision is up to the police commissioner.
Urban Pathways was still trying to get in contact with relatives of Mr. Lockhart.
Residents there described him as amiable and not shy about asking for a dime or a nickel. People called him “Pops,” Mr. Shack said.
The security guards, whose names were not released, had worked at Urban Pathways for more than a year. One guard, 28, had been released from the hospital and the other, 47, remained in recovery in the hospital, Nancy Olecki, a spokeswoman for Urban Pathways, said.
“This is so painful. This is someone who was well-liked by staff,” Mr. Shack said of Mr. Lockhart. “We will try to figure this out and try to get through it.”