Still gonna be virtually impossible to actually arrest them.
Sic semper evello mortem Tyrannis
97-17-67. Malicious mischief.
The law says that there has to be something destroyed for it to be malicious mischief. Nothing was destroyed or harmed by this group.
Plus, trespassing into a cemetery would also need to involve some form of destruction of property here (from what I've read).
Although distasteful, there really isn't much they can do about this, and even if it ever made it to court, it would very likely not amount to anything because restitution and fines are based on how much damage was actually done, which was none.
"A woman is like a teabag, you never know how strong she is until she gets in hot water." - Eleanor Roosevelt
Keep your religion out of other people's marriages.