And just a general note: out of all suggested assumptions here, mental illness is probably the best assumption you can make. We really don't pay nearly enough attention to this in America, and as a result our prisons are basically doing the old institutions' job.
Something like >50% of MA state inmates are suffering from mental illness, generally multiple illnesses. Statistically speaking, it's a safe bet.
It's also a real possibility when a person behaves in a way that's way out of proportion to whatever they are responding to. That said, vile criminals tend not to give much of a **** about human life, so this is an iffier basis for assuming mental illness than sheer statistic force.
Either she's one of those genuinely evil people who will now end up in prison for the rest of her life, or a seriously mentally ill person who will end up in prison for the rest of her life. If there's no father or grandparents in a position to care for the kid, the kid's orphaned. Some other people lost a grandfather, a father, etc.
Basically, as to the people making hilarious jokes about gun control, racism, and using it for political ends: [Censored] you [censored] [censored].