Ms Miller told FBI investigators that she put ricin in the food and drink of other residents on at least three occasions.
"Miller stated that she had an interest in plant-based poisons and had conducted internet research on how to make them", the Federal Bureau of Investigation said in a statement.
Miller allegedly told investigators and state health officials that she attempted to poison other Wake Robin residents using the homemade ricin. Dressed in protective gear, the team found a bottle containing Ricin powder in a wicker basket in Miller's kitchen cabinet.
Agents arrested Betty Miller on Thursday and charged her with unregistered possession of a select agent, ricin.
Kate Winslet and Stephen Colbert Recreate 'Titanic' Ending
Now, in honor of this landmark anniversary, Titanic is back in theaters for one week only, in a newly remastered edition. I turned 21 on that shoot but, I remember, having this so much feel like it was yesterday.
"No one is ill with ricin poisoning, and the danger for those who could have been exposed is over", said Ben Truman, a Health Department spokesman.
Last Monday, Miller drove herself to a hospital to be checked and is now being charged with possessing a biological weapon, a violation of federal law. No other cases of ricin poisoning have been discovered or reported in recent weeks through Vermont's illness surveillance system or by emergency responders, Truman said. When swallowed, Ricin can cause vomiting, bloody diarrhea, bloody urine, hallucinations and seizures.
Investigators also found a laptop computer and a sheet of instructions for making ricin that appeared to have been printed from the internet. She said she made the ricin in her kitchen at the Wake Robin senior living facility.
Miller told authorities she found instructions on the internet and over the summer harvested 30-40 castor beans on the Wake Robin campus.
Turkish Lira, Stocks Lose As NY Trial Implicates Erdogan
That probe was shut down after Turkish police and prosecutors in charge of it were accused of being supporters of Fethullah Gulen. USA prosecutors charge that the executive of Turkey's state-owned Halkbank, Mehmet Hakan Atilla, helped Iran launder the money.
"Ms. Miller indicated her goal was to injure herself, but she wanted to test the effectiveness of the ricin on others", Emmons wrote. By her own admission, she administered those substances to other residents in order to test their efficacy.
Miller was interviewed at the hospital Tuesday evening by the Federal Bureau of Investigation, and Vermont health officials.
Investigators have not said if additional charges would be filed. It said that it would not release details about its residents.
NBC5's Jennifer Sheahen is gathering more information on this developing story.
Russian Federation rejects USA call to cut ties with N Korea
The editorial called out the United States for "escalating hostility" in Asia and bringing the world closer to nuclear war. But Beijing and Pyongyang today are unlikely to find a compromise that also would satisfy the U.S.