Lawyers for Mr Li Shengwu yesterday presented to the Court of Appeal their arguments for quashing a court order that allowed the Attorney-General to serve papers on Mr Li in the United States for contempt of court.
Their arguments involved two points which the apex court told them and the Attorney-General's Chambers (AGC) to address.
The first is whether there was any statutory basis for the courts to exercise substantive jurisdiction over someone who was overseas at the time contempt proceedings started.
If the answer is yes, the second point is whether a new rule specifically allowing court papers for contempt to be served outside of Singapore can be applied retroactively, or if any other rules could apply to confer jurisdiction.
The AGC had served contempt papers on Mr Li based on existing laws, and is arguing that it is justified.
The rule allowing court papers to be served for contempt outside Singapore took effect in October 2017, a few months after the AGC started proceedings for contempt against Mr Li, who is Prime Minister Lee Hsien Loong's nephew.
Mr Li subsequently applied to set aside the High Court order, which was dismissed by a High Court judge who also rejected his request for leave to appeal.
He then sought leave to appeal to the Court of Appeal, and received the green light to do so last September.
Arguments on the case were heard yesterday by Chief Justice Sundaresh Menon and Judges of Appeal Tay Yong Kwang and Steven Chong in a packed courtroom.
Acting for Mr Li, lawyer Abraham Vergis from Providence Law said the portions of the law that the AGC was relying on did not provide a basis for the court to exercise substantive jurisdiction over someone who was overseas when proceedings started.
During the hearing, the judges took issue with AGC's Senior Counsel Francis Ng's decision to use a different portion of the Supreme Court of Judicature Act as the jurisdictional basis for his argument than previously.
This "essentially abandoned the position that the AG had taken up to that point", Chief Justice Sundaresh Menon said.
Responding to the Chief Justice, Mr Ng said: "I can only apologise and say that I wrongly assumed that the breadth of the question permitted parties the latitude we eventually took."
He made the case that the AGC's position on the jurisdictional basis "has not changed and will not change", and urged the Court of Appeal to dismiss Mr Li's appeal with costs.
During the hearing, Mr Vergis was also asked if Mr Li was in Singapore when he made the post in July 2017.
In the post, Mr Li said the Singapore Government is "very litigious and has a pliant court system".
It was made in relation to an ongoing family feud between PM Lee and his siblings over the fate of founding Prime Minister Lee Kuan Yew's house at 38 Oxley Road.
The AGC has made the case that Mr Li was in Singapore when he committed the offence, to support its application to serve court papers on him overseas.
Mr Vergis did not address the question. When pressed, he said: "Insofar as that appears to me the only evidence before the court, and there doesn't seem to be any contrary evidence, one can say it is possible for the court to consider that argument."
The Court of Appeal has reserved judgment on the case.