When met outside the Dang Wangi district police headquarters, the duo said they did so to avoid incriminating others at the gathering, held on the eve of Merdeka Day at Dataran Merdeka.
"In my opinion, the Janji Demokrasi rally was not against the law as it is the people's right to gather to commerate our independence struggle," said Chua.
Likewise, Mohamad who was accompanied by his lawyer Nazr Khan said he did not answer the questions.
Among others, the police requested for information on rally organisers, the number of participants and politicians who were present, he said.
Mohamad said they had a right to remain silent under Section 112 of the Evidence Act.
The duo was called to provide their statements as witnesses under the Peaceful Assembly Act 2012.
‘Will answer in court’
Also called for questioning was social activist Hishammuddin Rais who had arrived together with Mohamad at 4.15pm.
Tian Chua who is playing host to a Hari Raya open house event today arrived an hour later. He was not represented by a lawyer.
When met by reporters at around 6pm, Hishammuddin said a total of 21 questions were posed to him including a press conference held by rally organiser Gabungan Janji at the Kuala Lumpur-Selangor Chinese Assembly Hall prior to the rally.
"I did not answer most of the questions except for personal details. I will answer in court, he said.
Other questions that he did answer included the title of A Samad Said's poem entitled 'Janji Demokrasi' which was recited at the rally.
Hishammuddin was questioned under Section 9(1) of the Peaceful Assembly Act as a witness. He was accompanied by lawyer Faridah Mohamad.
On Thursday, Gabungan Janji leaders A Samad Said and Maria Chin Abdullah were also called up by the police for questioning but had similarly declined to answer any questions.