At least some content in this article is derived from information featured in Fantastic Beasts: Cases from the Wizarding World. Spoilers will be present within the article.
Don Harrison was a Muggle construction foreman. When beginning construction project in a forest that was home to magical beasts, his site and workers were attacked. Six of the workers walked off the job as a result.
During the subsequent Ministry of Magic investigation (during which Mathilda Grimblehawk and Mathilda Grimblehawk's partner, of the Department for the Regulation and Control of Magical Creatures, posed as Muggle inspectors from the local constabulary), his daughter Bethany went missing. A distraught Don Harrison pledged to level the whole forest to find her, before being calmed down by Mathilda, who assured him they would find his daughter.