I am all for contacting professionals. Stalking is potentially a life or death matter. You don't want to go with random advice from random people on the internet.
That said, if your professionals offer advice similar to what professionals in the past have told people that I know, this will be the basic message. Once someone has formed an extreme enough obsession that it becomes stalking, there is no easy way to let them down. Nobody can predict who will flip out, or what manner that will take. The legal system does not offer effective protection against people who have not actually broken the law yet.
Therefore people that I know who have talked to professionals in the field have been told that if the stalker has not yet turned negative, cut off contact, and be careful to avoid confronting the stalker with how unwelcome the attention is.