Prosecution seeks to impeach key witness in corruption trial of law prof

The Prosecution in the corruption trial of National University of Singapore (NUS) law professor has sought to impeach the credibility of its key witness, Ms Darinne Ko Wen Hui. 

It argued that there are discrepancies between Ms Ko's testimony in court on Friday and the evidence she gave to the Corrupt Practices Investigation Bureau (CPIB) in April last year.

Ms Ko, 23, is the key witness in the trial, dubbed the sex-for-grades case - involving her former professor, Tey Tsun Hang, 41. 

The prosecution had shown Ms Ko photographs of her and Tey, allegedly taken after they have had sex. 

When asked about some of the photos, Ms Ko said she couldn't remember when and where it took place. 

Apparently, this is not consistent with her statement to the CPIB. 

With impeachment, the judge will have to decide at the end of the trial which evidence to take into consideration. 

Earlier in the morning, Tey asked the prosecution to provide information on the grades of a few former students. 

He said he filed a criminal motion in the High Court in August last year to ask for information from NUS on the grades of Ms Ko and four other students who were called up by the CPIB during investigations. 

Tey had asked for the information to support his assertion that false confessions were extracted from him. 

Chief District Judge Tan Siong Thye ordered the prosecution and defence to sort out issue before continuing with the examination of Ms Ko.

Tey, a former district judge, faces six counts of corruption. 

He's accused of obtaining gratification in the form of gifts and sex from Ms Ko between May and July 2010. 

The gifts included tailor-made shirts, an iPod Touch and a Montblanc pen. 

The prosecution said these were inducements to show favour in his assessment of Ms Ko's academic performance.