THE CIVIL LAW INTERPRETATION OF "I DO NOT RECALL"

I tried to do research but I did not find any directly relevant information about what could be colloquially referred to as "Taking the Fifth". 

In civil court a decision is arrived at based on the preponderance of the evidence.

That is why I have diarized, emailed my MLA and published everything I could as accurately as possible about what did happen, what people did say and what the results of actions were.

It has been the tactic of people to claim they have no knowledge about any wrongdoing and they are not responsible for causing any damage. 

That would be "no evidence". That would be an indication that the respondent was hiding something. Detailed and evidence supported rebuttal would be required.