Evidence Code § 1223

Evidence of a statement offered against a party is not made inadmissible by the hearsay rule if:

(a) The statement was made by the declarant while participating in a conspiracy to commit a crime or civil wrong and in furtherance of the objective of that conspiracy;

(b) The statement was made prior to or during the time that the party was participating in that conspiracy; and

(c) The evidence is offered either after admission of evidence sufficient to sustain a finding of the facts specified in subdivisions (a) and (b) or, in the court’s discretion as to the order of proof, subject to the admission of such evidence.