What is the test for determining whether a spoliator has been responsible for the spoliating of a child?

A party seeking spoliation sanctions has the burden to establish the elements of spoliation by a preponderance of the evidence. McIntosh v. United States , 2016 WL 1274585, at *, 2016 U.S. Dist. LEXIS 44290, at *114-115 (S.D.N.Y., March 31, 2016), although the difficulty of establishing "relevance" varies depending upon the degree of the alleged spoliator's culpability, ranging from mere negligence to willful intent and bad faith.