Cops said Rajwinder Kaur, 26, who reportedly volunteered at a homeless shelter in Brooklyn, was last seen at her house on 198th Street Sunday night at 8 p.m.
She never returned, and the woman's sister received the cryptic text message about an hour-and-a-half after she disappeared.
"The girl with this phone is dead was smiling," the text read, according to NBC New York.
Police will not say if they suspect foul play, but have confirmed to DNAinfo.com New York that the woman was still missing as of Wednesday morning.
According to the Daily News, cops believe Kaur joined a cult, but it was not immediately clear why.
But her family denied this, according to the report.
Kaur is described at 5-foot-3, 130 pounds with a thin build and a medium complexion.
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