NEW YORK (CBSNewYork) — Neighbors are reeling after learning the death of an elderly woman in Brooklyn, initially thought to be from natural causes, has now been ruled a homicide.

The body of 82-year-old Myrtle McKenny was discovered by a home health aide alone on her kitchen floor in her sixth-floor apartment in Brownsville early last month.

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It was a closed case for investigators. A doctor signed off on her death certificate saying that she had died of  “complications from hypertension and diabetes.”

But as employees at the Caribbean Funeral Home on Nostrand Avenue began preparing her body for her burial this past weekend, they found stab wounds and broken ribs.

The Medical Examiner has now ruled that the cause of McKenny’s death was a stab wound to the neck and incise wounds to the right upper extremity with blunt force injuries to the head. She had three broken ribs and bruising to the face and neck.

The manner of death was homicide, the Medical Examiner’s office said. Hypertensive and atherosclerotic cardiovascular disease were contributing factors in McKenny’s death, the Medical Examiner’s office said.

Police said the doctor who signed off on McKenny’s death certificate had no way of knowing she was murdered.

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“The family doctor, as far as we can tell in our determination right now, never viewed the body,” said Chief of Detectives Robert Boyce.

Heartache over her death has now turned to anger and disbelief for McKenny’s neighbors.

“I can’t believe it, everyone is in shock,” neighbor Alana Garcia told CBS2’s Janelle Burrell. “I’ve been here 25 years, this is disgusting.”

“They find out that they killed her. I said, ‘What?’” said neighbor Eliana Garcia. “That lady don’t bother nobody. She was a good lady.”

“It’s something that you don’t want to hear,” said Irma Labiosa, who works in the building. “Someone you just see walking up and down the hall like that.”

Police have sealed and padlocked McKenny’s apartment as they continue to sift through evidence as part of the investigation.

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CBS2 reached out to McKenny’s doctor who signed the death certificate, but a request for comment has not been returned.