What is the test for reasonable suspicion to initiate an investigatory stop in this case?

We find that the officers lacked reasonable suspicion to initiate an investigatory stop in this case because the officers had no knowledge that plaintiffs had committed or were about to commit a crime. United States v. Hall, 974 F.2d 1201, 1204 (9th Cir.1992) (citing Terry v. Ohio, 392 U.S. 1, 30 (1968)).

According to the record, the officers received the following radio call: