NEW YORK (CBSNewYork) – A disabled grandmother was found dead Wednesday inside her Queens home with a knife stuck in her back.

Police said there was no sign of a forced entry and nothing appeared to be taken.

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Emotions were running high outside the Astoria Houses apartment building on Eighth Street in Astoria, as the victim’s son learned the gruesome news.

“Who killed my mom? Who killed my mom?” he screamed.

Minutes before, police were seen running into the building as other family members went inside.

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Police sources told CBS2 around 10 a.m., a home health aide and relative discovered the 64-year-old woman, identified as Donna Blanchard, face down in her sixth floor unit with a knife in her back.

“She was always in and out of her building. I always see her walking with her cane. I would never see her arguing or nothing like that. So it’s just like a surprise,” resident Nia Stith said.

Neighbors and family friends said Blanchard used a cane and wore a neck brace.

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The cause of her death remains under investigation.