What if every single one of those additional arrests is a Black person? Well that might require an additional look. It's possible that it's all Black people doing those crimes. It's also possible that the mathematician built an algorithm anchored on years of arrest data from racist cops doing racial profiling.
Will the mathematician be able to say, "hey cops can we take a second look?". No. Can the police be trusted to dig into the nuance themselves? Also no. Is racism active and documented in police departments across the country? Yes.
Should everyone who has any ability to do so stand up and say, we won't support this shit, which is what these mathematicians are doing? I think yes, but that's obviously my opinion.
That possibility is explicitly excluded since the data comes from crimes reported by victims, not investigations initiated by police officers.