I'd torture
Only thing is if, the baby were to die despite my best torturing, I'd continue to torture him till he died a bleeding mess, then I'd find his wife and do the same, then any of his kids, then his siblings, then uncles , aunts, cousins, all family individually tortured and killed, then his friends, work colleagues, his teachers, people who sold him his newspaper, anyone who had been in a photograph with him, all tortured and killed individually. Then people who had the same name, who looked a bit like him if you squinted up your eyes, then people who drove the same car, all tortured and killed individually.