Colo. Rev. Stat. § 1-13.5-1010
cord. (1) The vote of any absentee voter may be challenged in the same manner as other votes are challenged, and the election judges may determine the legality of such ballot. If the challenge is sustained or if the judges determine that the self-affirmation accompanying the absentee voter's ballot is insufficient or that the voter is not an eligible elector, the envelope containing the ballot of the voter shall not be opened, and the judges shall endorse on the back of the envelope the reason for rejection. When it is made to appear to the election judges by sufficient proof that any absentee voter who has marked and forwarded a ballot has died, the envelope containing the ballot of the deceased voter shall not be opened, and the judges shall make proper notation on the back of such envelope. If an absentee voter's envelope contains more than one marked ballot, none of the ballots in that envelope may be counted, and the judges shall note on the envelope the reason that the ballots were not counted. If an absentee voter's envelope does not contain all pages of a ballot, only the marked and returned pages shall be counted. Election judges shall certify in their returns the number of absentee voter's ballots cast and counted and the number of such ballots rejected.
Source: L. 2014: Entire article added, (HB 14-1164), ch. 2, p. 42, § 6, effective February 18.