What is the test for imputing a security guard's action against a defendant?

As to the second prong of the test, defendant contended the security guards were operating jointly with the police, therefore their action should be imputed to the state. The bases of the claim of joint operation were that the police also used the security office; the security guards had access to police radios, which they could have used to call the police and have them perform the search; the security guards exercised the authority of the state by arresting, handcuffing and searching defendant; the security guards were clothed with the indicia of state authority by virtue of their uniforms and equipment; and the security guards did not act for a purely private purpose. (People v. Taylor, supra, 222 Cal.App.3d at pp. 623-624, 271 Cal.Rptr. 785.)