The Federal Way man charged with killing his wife by poisoning her with a pesticide pleaded not guilty to the crime June 8.

Joseph Naimo, 62, is accused of killing his wife Ann Marie Naimo, 53, this past November. Toxicology reports revealed months after the woman’s death that she died from strychnine poisoning. The substance is used to kill pests. Alcohol and non-lethal levels of prescription drugs were also found in her system.

Joseph Naimo works in the pesticide business. He told police he found his wife unresponsive after the couple got into an argument over her drinking problem the day after Thanksgiving, according to court documents. He told the police Ann Marie had been drinking that day and had recently begun consuming alcohol after a period of soberness.

Federal Way police began investigating the death, which originally did not appear suspicious, in January, following the toxicology report. They arrested Naimo in May. He is being held in custody on $5 million bail.