Could a shrimp merchant at China's Huanan market in Wuhan be patient zero in the coronavirus pandemic? Investigations are beginning to point in that direction.

On Dec. 10, Wei Guixian, a seafood seller in the market, was feeling ill. Guixian sought treatment at a small clinic in the area and returned to work, possibly unknowingly touching off a global pandemic, which as of Friday had killed nearly 27,000 people worldwide, with over 585,000 confirmed cases.

A week later, the 57-year-old was barely conscious in a hospital bed, one of the first suspected cases in the coronavirus pandemic, reports the Wall Street Journal.

By the end of the December she was quarantined. Doctors had established a connection between her illness and others who had been at the market. The Wuhan Municipal Health Commission said Wei was among the first 27 patients to test positive for the coronavirus, and one of 24 cases with direct links to the seafood market.

Vendors who worked with Wei at the market, in addition to one of her daughters, a niece and the niece’s husband, also contracted the coronavirus.

Wei has since recovered and told the Wall Street Journal she believes she contracted the virus from a market toilet.