So, there was already reason to think that he might have known about the plan to cause gridlock in Fort Lee traffic as political revenge. Also, his approval rating in NJ was around 21%.
More recently when former Christie Chief of Staff, Bridget Kelly. testified in Bridgegate she stated that, yes, he knew about the plan a month before it was implemented. He has stuck to the story that he only became aware of the traffic mess after it had happened. Here is the coverage of Kelly's testimony.
In addition, Kelly added that she was afraid of Christie. He had a temper. That ranged from ranting to throwing an object. Therefore, it is possible, if we believe the testimony, that Christie was a bully even to his inner circle of staff.