Word for someone who knows what a person is going through but just doesn’t care

I am writing about an injustice for my English class and I need help figuring out a word to match this definition - someone who knows what a person is going through but just doesn’t care


A rather neutral term would be unsympathetic:

Not showing that you understand or care about someone's suffering

If you'd like something a bit more loaded you can go with heartless or unfeeling.