(CNN) Billionaire Democratic donor Tom Steyer called Friday for the impeachment for President Donald Trump, an issue he's pressed for months, in his response to the discovery of a suspicious package addressed to the philanthropist.

In the tweet, Steyer wrote, "We're thankful that everyone we work with is safe. We are seeing a systematic attack on our democracy that extends much further than just one isolated terrorist in Florida. That's why we are running an impeachment petition to end the culture of lawlessness in our country."

We're thankful that everyone we work with is safe. We are seeing a systematic attack on our democracy that extends much further than just one isolated terrorist in Florida. That's why we are running an impeachment petition to end the culture of lawlessness in our country. — Tom Steyer (@TomSteyer) October 26, 2018

Police in Burlingame, California, responded to a postal facility where a suspicious package addressed to Steyer was found Friday. He's one of the prominent political figures who were the intended recipients of suspicious packages, some carrying pipe bombs, including former President Barack Obama, Hillary Clinton, George Soros and others. Two of the packages, addressed to former CIA Director John Brennan and former Director of National Intelligence James Clapper, were addressed to them at CNN's offices.

A 56-year-old Florida man named Cesar Sayoc was arrested Friday in connection with 13 explosive devices mailed around the country, federal authorities said.

Authorities believe the package addressed to Steyer is from Sayoc, according to multiple law enforcement officials.

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