kicking off the plot

OK, the main characters of my story are a witch single mother and the stillborn trisomy 18 child that she ressurrected using a spell. The main plot is going to be another group of witches finding out about the child, deciding that he's an abomination, and trying to kill him.

Problem is, the kid's already 8 years old with nothing happening. How do I explain their sudden interest in him now?

What exactly do the other witches have against the child? That he has the condition, or that he was resurrected using a spell? Maybe resurrection spells have a price that needs to be paid in order for the spell to work, but the effects of the price hasn't shown itself until just now. Maybe death follows the child everywhere he goes, and maybe it's been true for him his whole life, but nobody's been able to connect the deaths to this child until now.

He's being kept alive by a magical spirit, and in some cases these spirits can be dangerous (they don't intend to be, but they have a lot of magical power and don't understand humans).

Anyway, what I was really asking is 'why now?' Why didn't they come after him when he was a baby?

Maybe they where searching for him (but not actively, just in a "kill on sigh" sense but without checking every kid if it's the one they're looking for), then he does something that calls the atention and allows them to figure out he's the one they're looking for (there might even be prior incidents).

Or maybe they just didn't knew what he was, they found out by whatever reason you preffer and then start actively trying to kill him.

Or maybe they just didn't feel like doing anything while he was a baby. They probably didn't think it was right to kill a baby. Maybe they respect the mother and didn't want to break her heart by re-killing the baby. Maybe they grew to treat the child like everybody else. But then something happens that changes their mind. The spirit thing does something dangerous and everybody realizes they can't let the child live any longer.