A 70-year-old woman living in a Vermont retirement home passed her time experimenting with homemade ricin, even testing it on fellow residents, the Justice Department said Friday.

No one had apparently been killed by Betty Miller's activities at the bucolic Wake Robin retirement home in Shelburne, Vermont, which advertises a population of "vibrant, engaged people and a community in which you can be yourself."

But Miller was arrested by FBI agents Thursday amid fears she had stockpiled a weapon of mass destruction.

The FBI was alerted to a dangerous substance at the home earlier this week, and discovered a bottle labelled "ricin" in her residence. Tests confirmed it contained the deadly substance.

"Miller stated that she had an interest in plant-based poisons and had conducted internet research on how to make them," the FBI said in a statement.

"She stated that she manufactured ricin in the kitchen of her Wake Robin residence and, to test its potency, placed the ricin in the food or beverages of other residents."

An FBI WMD team returned for a search of her apartment and found more ricin, and components from plants, including apple, yew, cherry, castor and foxglove, which all can be used to produce poisonous substances.