Well, they do have to investigate the complaint of a 16-year-old girl who has been forced to marry a 50-year-old lecher and bear his child. And since the girl appears to have indicated that other girls have been harmed or may be at risk of being harmed, the authorities would be derelict if they didn’t investigate further.
But first they have to prove that such a person even exists.
These "phone calls" are a common technique of CPS invaders. A member of their own staff usually gets someone to make the call, then they send the goon squad in.
Our constitution requires that the accused be confronted by their accuser. In these cases we really have neither accuser nor a specific accused. The warrants are clearly illegal.