Tran Kim Oanh and Le Ngoc Ha, both 41, will be investigated for "commission of fraud in performance of duties".

The two have joined the long list of university personnel placed under criminal probes for the same charge, including Tran Khac Hung, the university’s board chairman; Duong Van Hoa, its principal; Tran Ngoc Quang, deputy head of its student management and training department; and two other university staff.

The police are hunting for Hung, the chairman, who is absconding.

If found guilty, the suspects face up to five years in prison.

From late 2018 to early 2019, Dong Do University reportedly granted 600-700 secondary diplomas for VND28-35 million ($1,200-1,500) each. Secondary diplomas are usually given to those with at least one university degree for qualifying in a different subject.

The secondary diploma classes at Dong Do University did not announce any enrollment, have no examination board or an approved list of students and examination staff.

The university's board of directors arranged exams in rooms without security cameras and allowed students to copy the answers given by the examination staff, according to the police.

The police said that about 460 diplomas issued by the university have been used at many state agencies and private companies. The students with these diplomas are mainly cadres and civil servants who need foreign language diplomas and certificates to be eligible for salary raises and promotions.

The 25-year-old Hanoi Dong Do International University is one of the first private universities in Vietnam.