DailyKos:

Colorado representative Doug Lamborn has just made the final doo-doo step it what will be the shortest and most lackluster career the House has ever seen. Doug Lamborn's recorded threats to a pair of voters critical of his views has now reached the pages of both the Denver and Huffington Posts. Doug's local paper, the Colorado Springs Gazette, is eerily silent.[..]

Update: Here's the back story from Colorado Confidential. And here are Doug's threats, as printed by the Denver Post:

"Now there are consequences to this kind of thing , but I would like to work with you in a way that is best for everyone here concerned."

He didn't stop there, though. The message cut off before his inner Tony Soprano could kick in: