A Colorado surgery technician who authorities say is linked to at least 19 cases of hepatitis C has pleaded not guilty to charges of stealing syringes of painkillers and replacing them with dirty needles.
Twenty-six-year-old Kristen Diane Parker appeared in court Thursday on charges of tampering and illegally obtaining a controlled substance.
She could face life in prison if convicted.
Prosecutors say Parker was addicted to painkillers and exposed up to 6,000 patients at hospitals in Denver and Colorado to hepatitis C, an incurable liver disease.
The Colorado U.S. attorney's office says the investigation is continuing and more charges are possible.
Investigations have also been launched in Mount Kisco, N.Y. and in Houston, where Parker previously worked at hospitals.