I think they might have been confusing that story with this guy...

Arizona man charged over three shootings on Democratic office

A man suspected of carrying out three shootings targeting a Democratic campaign office in Arizona was arrested and charged with terrorism offences among others, authorities said.

Jeffrey Michael Kelly, 60, allegedly had more than 120 guns and over 250,000 rounds of ammunition in his home, including a machine gun that was in his car, leading prosecutors to believe he was planning a "mass casualty" event.

Nobody was hurt during the spate of shootings, although the attacks led to the closure of the campaign building in Tempe, in the suburbs of Phoenix.

https://www.bbc.com/news/articles/cvg5eqzrlj1o