Another report flew across Facebook, written by a New York D.J. who goes by Max Mayfield. “Wow im shocked from the news I just got!! At 711 Beach 6 in FAR ROCKWAYS they carried out 3 dead bodies!!!” Mr. Mayfield, who had volunteered at the Sand Castle earlier in the week with Ms. Balandina, had heard about the bodies from a friend who had heard it from someone else and thought he had seen one.

Cheers erupted at the Sand Castle when the lights came back on the night of Nov. 10. The utility had restored power just 40 minutes before two immense generators provided by the city arrived, Mr. Sanchez said. Meyer Brecher, the senior manager, said he had spent days calling the utility company, as well as city, state and federal officials for help restoring power. “The only one I didn’t get to is Obama,” he said.

Some officials dispute receiving some of the Sand Castle’s requests or the timing of them, though they acknowledge they were overwhelmed by the demands across the city.

Mr. Sanchez worked to bring back running water and heat in the days that followed. He had not gone home to his children or taken a day off in two weeks, instead staying in the complex where he had worked for more than a quarter-century. Heavyset and middle-aged, he had climbed staircases and placed numerous calls for help. And he maintained a handwritten, often-changing list of some 200 apartment numbers where the most vulnerable still resided.

Shortly before the power came back, volunteers mentioned that no one in Apartment 13C had responded when they offered food. Mr. Sanchez asked a visiting nurse, who was on her way to give an insulin shot to one of Mr. Anderson’s neighbors, to knock on his door. There was still no answer. Mr. Sanchez sent maintenance workers up on the morning of Nov. 12 to check on a few apartments including Mr. Anderson’s, but there was still no reply.

Later that day, Mr. Sanchez went upstairs with a police officer. There were no National Guard markings on the doors of the 13th floor in Building B, suggesting the corridor may have been missed. The two unlocked Mr. Anderson’s door and called for him. Mr. Sanchez saw bare feet sticking out from the other side of the bed. It was not the first time he had come upon a scene like this.

Mr. Anderson’s neighbors were distraught over news of his death. Mr. Martinez lighted a candle in front of his door and spoke about him at a tenants association meeting. He blamed the owners, who did not send a representative to the meeting, for not doing more to help the elderly. He suspected the owners wanted to fill the Sand Castle with younger, more affluent tenants.