Concur with @Tron, document EVERYTHING. Include witnesses, quotes, EVERYTHING. And send it to multiple folks: DE, SE, COR, etc.
Closest I have had to deal with was on camp staff. A Scout was being sent home for behavior reasons, but was hit by an adult, and had a black eye. Mom made comments about YP and reporting the issue. What she didn't know was her son, after he was told to pack his things because he was going home, picked up a stick, and charged the 18 y.o. ASM. The ASM automatically countered the attack. OH and he attacked the ASM in front of the SM and the entire troop while they were getting ready to go to dinner. LOT OF PAPERWORK WITH THAT ONE! ( major emphasis, not shouting.)
Moral is DOCUMENT, DOCUMENT, DOCUMENT! (again, emphasis).
Good Luck.