Can people of color be racist?

When we were discussing racism in class a question came up " Can people of color be racist". Usually when we talk about racism we only think about white being racist towards people of color, we never think about people of color being racist towards other people of color or people of color being racist towards white.
In the Tatum article author said that people of color can not be racist. But if we believe that one group having advantage over another graoup is racism then people of color can be racist. I know a person who worked at a small business which was own by a minority, had to quit his job because owner supported employes who were from his own group and he was racist towards him. And we also heard from one of our classmate that he experienced racism from other minority group. So i think just because you are a minority group it doesnt mean your action or belief can be any less racist than those of the majority group.