CARSON CITY, Nev. — A 74-year-old man accused of threatening a Carson City judge has pleaded not guilty to three felony charges.

John Aston is facing charges for fourth-degree arson, aggravated stalking and discharging a firearm into an occupied dwelling. The Carson City District Attorney’s Office said Tuesday that Aston has waived his right to trial.

Investigators suspected Aston of threatening Judge John Tatro after his DNA matched with evidence left on a Christmas card sent to Tatro in 2013 containing death threats. Tatro had presided over two cases involving Aston.

Aston was sentenced to 12 to 32 months in prison in August for unrelated weapons charges.

His trial’s is set to begin May 30, 2018.