Another former student of law professor Tey Tsun Hang took to the witness stand on Tuesday, in the sex-for-grades corruption trial.

Mr Colin Seow - now an Assistant Registrar at the Supreme Court - revealed to the court, the circumstances leading to the purchase of a printer for Tey, who is facing charges of corruptly obtaining gifts and sex from former student Darrine Ko.

It is the first time that another former student of Tey has appeared in court, since Ms Ko testified for the prosecution in the early part of the trial.

Mr Seow told the court that there was never an intent" to buy the printer as a gift for Tey right from the onset, and that Tey had reimbursed him for the printer - facts he said were made clear to the Corrupt Practices Investigation Bureau (CPIB) on April 3, last year.

Earlier in the trial, Tey had said his confessions to teh CPIB were "riddled with falsities", including a claim that he had corruptly received the printer from Mr Seow. But the prosecution said on Monday that CPIB would not have elicited statements they already knew were untrue, said Deputy Public Prosecutor Andre Jumabhoy.

The DPP had said that Teys six statements included many red herrings to "throw CPIB off his scent" to "buy time", and to "undermine" each real confession by "laying the grounds of something untrue".