The American definition of plagiarism, believe it or not, is different from most of the rest of the world. Our office is very aware of this difference, and we spend some time in orientation and with individual students trying to explain the concept of cheating. We need your help. Be explicit and firm. Address the issue of citation with examples.
More international students come here as graduates than undergraduates.
Most will therefore NOT have taken English 102, and have never heard of the concept of citation. In some academic cultures outside the US, sharing information is what would would call stealing information. It is a new concept. Again, if you need help with this. Talk with the student.