Back in my university days, tools were used to detect suspected cheating, but actual confirmation comes only after interviewing the students in question. This

Back in my university days, tools were used to detect suspected cheating, but actual confirmation comes only after interviewing the students in question. This is especially important since if there are two or more pieces of homework that looked similar, you want to know who wrote the original. Failing the whole class without such follow up interviews seems unreal.