I,too,am a Christian...a noticeably imperfect one.But tell me....if one or both of a child's parents fail that child in a substantial way,in a completely avoidable way...can that parent be held responsible to any degree for the child in question "going wrong"?
I think you know what I'm driving at and I have no evidence that that happened with Martin but I still have the hunch that it did.
If you mean by God, yes he can, and the parent had best repent like any of us.
If you mean by me, well its not my job to hold people morally accountable beyond how it is my responsibility in culture (for example, I would not want irresponsible adults to look after my children, or those of others if I were in charge of a school etc).
The hard part of the question is how far the law ought to hold parents accountable for things their children do due to bad influence. And I guess there are some cases where it would be clearly appropriate...like a parent encouraging their 5 year old shop lift...and those where it was clearly not appropriate, and those in between.