VISTA, Calif. -- The former executive director of the North County Humane Society pleaded not guilty Monday to a felony charge of fraudulently obtaining a prescription.

Deputy District Attorney Richard Madruga alleges that Stacy Steel used the federal drug registration numbers of three veterinarians to acquire 3,600 tablets of hydrocodone -- commonly known as Vicodin -- between last August and February.

Vista Superior Court Judge Aaron Katz allowed the 37-year-old defendant to remain free on $10,000 bond and set a readiness conference for May 11.

Steel, the subject of an investigation by the federal Drug Enforcement Administration, resigned from her $95,000-a-year job on March 25 after leading the local Humane Society for three years.

The defendant, who faces a maximum of three years in prison if convicted, allegedly told DEA investigators the pills were for her dog.

One of the veterinarians, Jennifer Stewart, told the North County Times that Vicodin is not normally used in veterinary offices.

The North County Humane Society, as a licensed handler of veterinary drugs, is monitored by the DEA. It runs a shelter in Oceanside and provides animal-control services under contract with the cities of Oceanside and Vista.