"The first tour guide was up front. She didn’t have any bear spray or protection from wildlife on her, but the guide that was in the back of the group did. And unfortunately there was about 20 people between them. When the attack happened, he ran up to the front. All the other people took off. He sprayed the bear as it was mauling the first victim and was able to get it off of her. There were some wounds inflicted on him that were rather minor. After that the bear took off.”

The KCAW article has more specifics including the above documentation that bear spray,  when in hand, did its job. 
http://www.kcaw.org/2016/08/19/wilderness-guide-medevacked-after-bear-mauling-in-sitkoh-bay/