Colorado Public Radio: Members of the youth-led climate activist group Sunrise Movement distributed a fake letter to attendees at the start of the Dec. 5 Sustainable Denver Summit.

The letter appeared to be on city letterhead, but was actually written by the Sunrise Movement, who are known for using unusual tactics to make their point.

The disinformation campaign also played out on Twitter. As the event got started and Mayor Michael Hancock took the stage, Sunrise Movement tweeted out the letter.

Visit Colorado Public Radio for more.