A 70-year-old woman from Queens, New York, was recently arrested after her husband caught her lacing his coffee with boric acid.

Robert Baron first noticed that the food his wife cooked for him tasted funny back in September 0f last year. He also started feeling sick after meals, and on some occasion he would get so tired that he slept for 15 hours at a time.

Suspecting that something fishy was going on, the 63-year-old man installed a small surveillance camera in the kitchen, without telling his wife of 11 years, Suncha Tinevra. That’s how he caught his partner lacing his coffee with a chemical used to kill cockroaches.

Last week, upon checking the camera, Baron saw his wife dump some sort of powder into his coffee. After seeing the footage, Baron walked into the 111th Precinct and reported his wife to the police. Tinevra was arrested soon after, and the coffee pot and coffee from the couple’s home were seized for testing.

It turns out that the elderly woman had dumped boric acid into her husband’s coffee, which she later admitted to, adding that it hadn’t been the first time.

“I’ve done this two or three times, I don’t remember when, just when I’m angry,” Suncha Tinevra told police. “I just wanted to teach him a lesson.”

The 70-year-old woman was released last Friday without bail, but with an order of protection forbidding her to go near her husband.

Boric acid is a white powder that is widely used in various fields. It’s sometimes used as an antiseptic to treat light burns or cuts, but also as an insecticide against cockroaches, ants and other insects. According to an affidavit from a case similar to the one presented above, a tablespoon of boric acid is enough to kill a 150-pound man.