Following Hyland's model of metadiscourse, evidential is defined as an expression that references information from other texts. Evidence in traditional academic writing may include peer-reviewed articles, published books and personal communication with field experts. With a sharp increase in the use of online teaching and learning environments by education providers, such as Google Classroom and Canvas, and a vast range of sources of evidence available in non-traditional forms, are types of evidence in students' academic writing changing and, if yes, how? In this study, we analysed the use of evidentials in course discussion forums by students at the Universiti Brunei Darussalam, revealing the types of evidence included in the writing. Our findings show that students' academic writing in online teaching environments expands what is traditionally considered academic evidence to some extent, but more targeted teaching intervention may be needed to broaden the range and quality of evidentials used by students.