Police arrested Tigrayan street trader Nigusu Mahari last year as he strolled along the traffic-clogged streets of Ethiopia¡¯s capital Addis Ababa. He says he was speaking on the phone in the language of his homeland, a distant region in the north.

Officers accused the broom hawker of planning a bombing, trying to overturn the constitution and working with Tigrayan rebel fighters. Nigusu professed his innocence. Six weeks later, a judge released him on bail without charge, court records show, after Reuters began inquiring about his case.

Nigusu is among thousands of Tigrayans swept up in a nationwide crackdown that started last November, when fighting erupted in Tigray between federal forces and the Tigray People¡¯s Liberation Front (TPLF), the party that dominated the national government until three years ago. Tigrayans themselves are a small minority in Ethiopia¡¯s mosaic of more than 90 ethnic groups and nationalities.