Police in a southern city are mulling criminal detention of a college student who stabbed his professor this week after the latter declined to increase his thesis grade.

Tran Quang Dong, the suspect, has given himself up to the police in Can Tho City, local officials said Sunday.

Dong, a law major, defended his graduation thesis before a council that included Dr Pham Van Beo – who taught him at university.

The council gave him a C, an average grade, which he feared would make it hard for him to find a job later on.

The student then went to Beo’s house on Friday to plead for a grade hike but the professor turned him down point blank.

Dong immediately stabbed him in the back with a knife, causing the educator to be hospitalized for one hour.

Beo’s internal organs were not hurt and his life was not threatened, doctors said, so he was discharged after having his 2-centimeter wound stitched.

The Can Tho police said Dong showed signs of mental distress during their investigation so they will get him tested.

A vice police chief said they did not rule out a possibility that the student will be placed in criminal detention after the test.