Colo. Rev. Stat. § 30-10-710
It is the duty of the county treasurer to apportion and keep all taxes collected by him or her in the several funds for which the taxes were levied, and it shall not be lawful to use the moneys belonging to any fund for the purpose of paying warrants drawn upon some other fund or for the purpose of paying warrants issued before April 2, 1998, which properly should have been drawn upon some other fund; but the amount of interest gained through the investment of county funds, regardless of the origin of such funds, may be credited to the general fund of the county by the county treasurer, unless such investment is made from specific funds allocated for a definite purpose and so maintained. The treasurer and the sureties on his or her official bond or the insurer on the crime insurance policy, as applicable, shall be liable at the action of any taxpayer of the county for any violation of this section.
C.R.S. § 30-10-710