Both are poor choices. There is no job that requires a Criminal Justice degree. It's a degree that cops usually get in night school to pad their resumes. It's certainly not required for law school. If you want to be a cop, apply to be a cop.
Social work is equally useless and financially stupid. Social work pays a pittance and the burn-out rate is huge. You need an MSW in order to do psych counseling which doesn't pay much more.