Colorado Law:If your state doesn't have a citizens arrest law, look for a "Common Law" statement, such as this in Colorado's revised statutes:16-3-201. Arrest by a private person.
A person who is not a peace officer may arrest another person when any crime has been or is being committed by the arrested person in the presence of the person making the arrest.So even if it's not enumerated specifically, it would be covered.
2-4-211. Common law of England.
The common law of England so far as the same is applicable and of a general nature, and all acts and statutes of the British parliament, made in aid of or to supply the defects of the common law prior to the fourth year of James the First, excepting the second section of the sixth chapter of forty-third Elizabeth, the eighth chapter of thirteenth Elizabeth, and the ninth chapter of thirty-seventh Henry the Eighth, and which are of a general nature, and not local to that kingdom, shall be the rule of decision, and shall be considered as of full force until repealed by legislative authority.