Mr Lai, a 76-year-old UK citizen, is facing the prospect of life in prison if found guilty of the charges brought against him under the draconian national security laws. He has pleaded not guilty to the charges of sedition and collusion.
Cheung Kim-hung, a former Apple Daily chief executive, on day 13 of the landmark national security trial in Hong Kong said Mr Lai instructed the newspaper's editorial staff to contact bookseller Lam Wing-kee for an article that would mobilise the mass, South China Morning Post reported.
Mr Lam was detained in 2015 and later abducted for selling controversial publications about China's leaders that were banned in the mainland. He moved to Taiwan after a bill was proposed which would have allowed people in Hong Kong to be sent to China to face trial in courts controlled by the Chinese Communist Party.
The bill was later withdrawn by the government. But mass demonstrations over the bill evolved into pro-democracy protests that rocked the city for months.
In a Whatsapp message shown in court, Mr Lai told Mr Cheung: "We will use Lam Wing-kee’s story to boost the mass rally on the 28th".
“However, in order to make it a headline story, [we] must approach Lam for a telephone interview. Please contact Lam and make this happen. Thanks," the message read.
Mr Lai also approached former Hong Kong governor Chris Patten through British human rights activist, Benedict Rogers, for a comment on the proposed bill, the court heard.
A day after running the report on Mr Lam in April 2019, the newspaper published a statement from Mr Patten, calling the bill an "assault on Hong Kong’s values, stability and security”.
Mr Cheung, who worked for Mr Lai for nearly 30 years, testified that the media mogul pushed two more stories to bring more people onto the streets. He added that Mr Lai also supported his proposal to donate one-third of the newspaper's subscription proceeds to the protesters.
Defence counsel Steven Kwan Man-wai during Friday's proceedings said Mr Laid had difficulty keeping up with the evidence displayed in court due to an eye problem that had deteriorated following an operation.
Mr Cheung previously testified that his boss had instructed the editorial staff to use the newspaper to encourage people to join protests in Hong Kong and draw the attention of Western nations.
On Thursday, she said Mr Lai instructed him via WhatsApp to highlight the meeting between then vice president Mike Pence and Hong Kong’s former chief secretary Anson Chan to "use it to the maximum effect".
Mr Cheung is one of the six former Apple Daily staff to plead guilty in November 2022 to conspiracy to commit collusion with a foreign country.
Other prosecution witnesses include former associate publisher Chan Pui-man, former editorial writer Yeung Ching-kee, activist Andy Li and paralegal Chan Tsz-wah. They have all pleaded guilty and will be sentenced at the end of the trial.