I just saw a post with someone questioning the usefulness of an Amber alert 400 km away from where a vehicle was spotted¹ and wondered if the alert itself would indiscriminately be sent to every phone in a target region, and if that would include the phone of the person of interest, which would seem counterproductive at best.
¹ I pointed out that the car might be known to travel to that region, even if it was last seen 400 km away.
The vast majority of amber alerts are parental custody disputes (at least from California data), so yes, they know the abductors phone number, name, home, workplace, social security number, relatives, etc