Was there a prominent Samaritan scholar at the time of Josephus
Flavius, the jewish writer/

Check out http://www.earlyjewishwritings.com/thallus.html.
It references:
  http://www.infidels.org/library/modern/richard_carrier/thallus.html
  http://www.infidels.org/library/modern/richard_carrier/jacoby.html

Thallus may have been a Samaritan historian at that time, but as the
above articles describe, not everyone agrees that he was Samaritan.