Wichita ? Charles Koch, the billionaire industrialist who has funneled millions of dollars into conservative causes and candidates, says he and his brother have been getting death threats and hate messages in recent months.

The comments from the head of Koch Industries, one of the nation’s largest privately held companies, came in a rare interview Thursday on the eve of a three-day protest dubbed “Occupy Koch Town,” which is expected to draw hundreds of activists upset with the billionaire brothers’ influence on politics and government policies on climate and the environment.

“We are under attack from various directions, both with threats of violence against us personally, and with threats of attacks on our businesses,” Koch told The Wichita Eagle on Thursday.

Among some of the emails released was one saying, “The Koch brothers will DIE!!!!!” ”Choose your expiration Date, Brothers …” another said. “I hope you all DIE,” one said last year.

Wichita Police Lt. Doug Nolte said Friday that the last reports the department had on file from Koch were in 2010 involving a complaint about someone putting signs on his property and a 2009 arrest for trespassing at his house.

Koch Industries general counsel Mark Holden told The Associated Press that the death threats were reported to the FBI because they crossed state lines. One involved a telephone call last year from California in which the caller threatened to put a bullet in the heads of both Koch brothers. Others involved online postings advocating the Kochs’ murder.

An FBI spokeswoman did not immediately return a call for comment.

Koch said he has merely exercised his free speech rights in taking political positions and supporting causes.

“I have been involved in trying to advance freedom and prosperity for 50 years now, and because we are considered by some to be more effective, we are often the focus of these attacks,” he said. “But I have decided there is no way, after spending two-thirds of my life speaking out about these matters, that I’m going to quit doing it now.”

Wichita-based Koch Industries decided to go public with the emails on the day before hundreds of activists were expected to gather in Wichita for three days of “Occupy Koch Town” events.

Yvonne Cather, conservation chairman for the Kansas chapter of the Sierra Club, one of the groups organizing the event, said the Koch people are overreacting to the planned activities.

“The Sierra Club prides itself on high integrity, so violence is not the way we want to get our point across,” she said.