How exactly did the girl die (what caused her to stop breathing)? I didn't see that. If possible, push for 2nd degree murder, but if it was because of "punishment," they may not be able to get 2nd degree. In that case, push for voluntary manslaughter and child abuse charges.
Here it is:
According to the authorities, forceful and numerous whippings, apparently with plumbing line, may have caused tissue breakdown so massive that Lydia's vital organs could no longer function.
So basically they beat her so much and so severely that her body just couldn't cope with it and it shut down.
As far as charging manslaughter instead of murder, I don't think that's going to fly. While they may not have intended to kill the girl, it was a foreseeable consequence and their torment of her was planned and systematic. I stress the word torment - this was torture as it went far beyond ordinary child abuse. This is a serious crime, and if a death is caused in the commission of another serious crime it can be legally considered murder.
Yeah, I didn't see that - definitely go for 2nd degree murder.