Whether law professor Tey Tsun Hang had breached the anonymity of his university's marking system was the subject of Tuesday morning's hearing. Six months before former student Darinne Ko was to sit for an exam for a module he taught, Tey received an e-mail with her matriculation number, the court heard.

This, argued Deputy Public Prosecutor Andre Jumabhoy, breached the university marking system's anonymity safeguard, in which the author of each exam script is only identifiable by the matriculation number rather than a student's name.

But Tey, who is charged with six counts of corruptly obtaining gifts and sex from Ms Ko in exchange for boosting her grades, countered that a student's matriculation number is used "for all sorts of registration purposes", and that as a professor he received "many emails" from students that might contain their matriculation numbers.

He conceded however to Mr Jumabhoy's point that Ms Ko's email in question had been sent to his personal account, rather than his NUS account, although he did not reply to it. Earlier, when asked if being the sole lecturer and marker gave him a great deal of power to decide the outcome of his course, Tey replied: "Yes, with power comes responsibility." The DPP countered: "I think that's from Spiderman, isn't it?" To which Tey said: "I'm sorry I did not know that. I'm educated (by you)."