The profanity-laced e-mail was sent after Councilmember Charlie Brown backed out of an interview with a cable TV show focusing on saving pit bulls.
Since 1989, pit bulls have been banned in Denver. Brown supports the ban.
"Every time we talk about pit bulls in Denver on city council, we get a lot of, frankly, hate mail," Brown said.
Brown says a recent pro pit bull e-mail went too far.
"They certainly have the right to their feelings, but think twice about sending e-mails like this. It's silly. It's stupid," Brown said.
The e-mail was sent to Brown after he backed out of an interview with the Pit Boss TV show on the Animal Planet network.
"After the Tucson tragedy, I just said, 'You know, maybe this is not the time to go on that show,'" Brown explained.
The alternative weekly, Westword, published an article about why Brown declined the interview, and then he received the e-mail.
One line says "Your (sic) afraid because of what happened in Arizona and you should be."
"That's a pretty serious statement," Brown said.
The e-mail also says "ALL government officails (sic) should be aware of what comes with the job..."
"What does he mean by that? That you should be prepared to be shot?" Brown asked.
Brown forwarded the e-mail to police, and they are investigating.
He met with officers on Saturday to provide them with documentation.
"He says there's nothing wrong with what happened in Arizona. That's just normal in the course of your business as a public official. This is loony tunes, and this is wacko," Brown said in reference to the hate mail he received.
David Edelstein leads a pro-pit bull advocacy organization.
"He's not with our group; he's not of our camp of thinking at all," Edelstein said.
While he disagrees with Brown's stance on the pit bull ban in Denver, and would like to see it overturned, Edelstein says he doesn't condone the tone of the e-mail.
"We do not endorse violence, we do not endorse threats, and we'd rather engage the city in a point, counter-point debate over the issue," Edelstein said.
Edelstein is hoping to get the issue on the ballot soon so voters can decide whether to repeal the ban.
"We're going to do this on the political stage," Edelstein said.
That is an approach Brown is okay with.
We reached out to the person who e-mailed Councilman Brown for a comment, but 9NEWS has not heard back from them.
(KUSA-TV © 2011 Multimedia Holdings Corporation with The Associated Press)