The Pulitzer Prize-winning journalist who broke the story on American researcher Shane Todd's death will be "welcome" if he decides to testify at the ongoing coroner's inquiry, the State Counsel said on Friday evening.

Speaking to media after Friday's proceedings, in which four of Dr Todd's colleagues, including his former supervisor, disputed parts of Mr Raymond Bonner's February 15 Financial Times article titled "Death in Singapore", Senior State Counsel Tai Wei Shyong said he understood that Mr Bonner was in Singapore,

"On my part, the State would be happy to make the application (to the Court) because we want the full story about this case to be told," said Mr Tai.

Replying to queries from the media, Mr Tai also said that the unknown fragments of DNA found on the strap and towel around Dr Todd's neck were confirmed by the Health Science Authority's DNA analyst Kua Guo Wei as possibly weeks, months or even years long, even if the items had been washed.

Mr Kua had on Tuesday also said that in cases of multiple DNA samples, there was no way to establish through tests whether all the DNA contributors had left their DNA at the same time.

When asked later if he wished to testify, Mr Bonner, who has a graduate law degree from Stanford Law School, said: "Do I get to cross-examine witnesses?"