An Arizona woman is accused of using bleach to poison the coffee of her estranged husband, a member of the Air Force, over several months, according to court documents.

Melody Johnson was arrested July 18 after her husband submitted video to police allegedly showing her pouring the toxic substance into his coffee machine, authorities say.

The man, who is not named in court documents, started noticing that his coffee tasted badly at the end of March while he was stationed in Germany, court documents say.

Johnson and her husband are going through a divorce but lived together with their child.

The man continued to drink the coffee for two to three weeks before he used chemical testing strips to test the water in his faucet, which came back normal, according to court documents. When he tested the water in his coffee pot, it showed “high levels of chlorine,” the documents say.

In May, the man set up a camera in the home, which showed Johnson “pouring something into his coffee pot,” according to the complaint, which said he pretended to drink the coffee until the family came back to the U.S. on June 28 because he didn’t want to file a report in Germany.

While he was temporarily stationed at a hotel on Davis-Monthan Air Force Base in Tucson, Johnson’s husband set up another camera, which again showed Johnson “walk to his coffee maker and pour something into his water reservoir” on July 5, court documents alleged. The man filed a police report the next day, but officers told him it wasn’t clear what Johnson was pouring into his coffee pot, they said.

When the family moved to permanent housing on July 7, the man set up more cameras that looked like fire alarms to the ceiling, according to court documents. One was placed in the laundry room, where bleach was kept, another was placed right over the coffee machine, and a third was placed to show walking between the two areas, the documents said.

After he collected multiple videos allegedly showing Johnson “take bleach, pour it into a container and then walk over and pour it into the coffee maker,” her husband went back to police, court documents say.

The man told police he believes his estranged wife was trying to kill him to collect death benefits, police said.

Johnson was arrested by Tucson police and charged with attempted first-degree homicide, attempted aggravated assault and adding poison to food or drink. She was being held at the Pima County Adult Detention Center, according to online records.

A search with a warrant recovered a container with liquid in it in Johnson’s bedroom under her bathroom sink that smelled like bleach, according to court documents, which said liquid inside the coffee maker also smelled like bleach.

It wasn’t clear whether Johnson has an attorney.