Quote Originally Posted by Trigg3r Happy View Post
Here we go
18-1-701.
Execution of public duty. (1) Unless inconsistent
with other provisions of sections 18-1-702 to 18-1-
710, defining justifiable use of physical force, or with some
other provision of law, conduct which would otherwise constitute
an offense is justifiable and not criminal when it is
required or authorized by a provision of law or a judicial
decree binding in Colorado.
(2) A “provision of law” and a “judicial decree” in subsection
(1) of this section mean:
(a) Laws defining duties and functions of public servants;
(b) Laws defining duties of private citizens to assist public
servants in the performance of certain of their functions;
If I read that right, it just says you're not committing a criminal act by tackling someone if an officer asked you to do so. It doesn't state one is bound to assist.

I'd also like to know if there is a statute which would require one to assist if asked. I would be surprised if such a law did exist. I'm pretty sure an officer can't make me tackle someone.