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Police identified the woman as Lorraine Maradiaga, 18. She stands to be charged with terroristic threat, Texas Penal Code 22.07, they said.
"We have no confirmation Maradiaga is actually a threat to public health," the department announced on Facebook Sunday night. "We are, however, taking her social media actions very seriously."
The woman allegedly recorded herself shopping at what she claimed to be a local Walmart, according to Fort Worth's KXAS-TV.
"I'm here at Walmart about to infest every [expletive] because if I'm going down, all you [expletive] are going down," she allegedly said in the Snapchat video.
A police spokesman told the station that officers went to her home on Sunday, but she wasn't there. Police added that her family was cooperating with them.
Texas has 7,294 confirmed COVID-19 cases and 140 deaths as of early Monday, according to data from Johns Hopkins.
Anyone with more information is asked to call 972-466-3333 or email CrimeTips@CityofCarrollton.com.