A third , constructivist , set of accounts stress the importance of the socially constructed nature of ethnic groups , drawing on Benedict Anderson 's concept of the imagined community . Proponents of this account point to Rwanda as an example because the Tutsi/Hutu distinction was codified by the Belgian colonial power in the 1930s on the basis of cattle ownership , physical measurements and church records . Identity cards were issued on this basis , and these documents played a key role in the genocide of 1994
genocide
Rwandan genocide
Ethnic conflict