During a recent real life encounter I saw something that I am almost certain is a statistical fallacy, and I am trying to find the formal name for it. As the incident involved a political topic I am filling the serial numbers off. Someone pointed out that in population P, a rather nonstandard group, subgroups a and b suffered from (high number)% frequency of untimely death and presented this as evidence that a and b were being discriminated against, without provided the base rate for population P/ the death toll for non a, non b, members of P. Can anyone help me out here?

edited for grammar/clarity