As is common in natural disasters, accurate information was scarce. On Tuesday, Mr. Lincoln told MSNBC, “She is now with her family, they say, and doing just fine.” He had gotten an address, he said, so he could return her dentures.

But Ms. Ellis’s family did not know where she was.

They called hospitals and shelters. They got in touch with Mr. Lincoln, who joined the search by posting on social media and doing follow-up interviews. One man said he had seen her at a shelter. But still, no one could find her.

It was not until Thursday that Ms. Davis received a call from the morgue.

Combing Through Clues

Ms. Ellis, who spent her childhood picking cotton in rural north Louisiana and later worked at a hospital in Houston, was a matriarchal figure in an extended clan — she had seven siblings, six children, grandchildren and great-grandchildren. They called her Mama, or Jean.

To find her, they had been sifting anxiously through the meager clues, left like shreds of storm debris snagged on a chain-link fence. But now that they knew she was dead, those clues refused to add up. How, if she had nearly drowned, had the turban remained on her head? In the photograph taken by Mr. Lincoln, didn’t she look dry?

More important, where had she been left, and with whom? Had there been foul play? Or had someone, some of them wondered, simply failed to care enough about a lone, old black woman?

The red tape did not help. Her son, Carl Ellis, went to get her medical records, but came away empty-handed because he had no death certificate. The autopsy report would not be available for weeks. Ms. Ellis had been identified using fingerprints, the medical examiner’s office said.

But there was an official cause of death: drowning. That raised more questions — if she had been revived, how had she drowned? Had she been fished from the water only to be swallowed up again? Could she have gone through something destructive enough to wrest the hospital bracelet from her wrist?