He pointed to a similar case in 2014, when Canadian Christian aid workers Kevin and Julia Garratt were detained shortly after Canadian authorities arrested a Chinese national in connection with a hacking case in the US.
Mrs Garratt was released on bail and allowed to leave China in 2016.
China charged Mr Garratt with espionage but allowed him to leave the country in 2016, months after the Chinese citizen, Su Bin, agreed to go to the US and pleaded guilty.
The authorities have yet to confirm Mr Kovrig’s legal status but the Beijing News, a local newspaper, reported that he is under investigation on suspicion of “engaging in activities that endanger China’s national security” – a phrase often used in espionage cases.
In another twist, Canada said a second Canadian was being questioned by Chinese authorities, with The Globe and Mail reporting the person as Mr Michael Spavor, who is based in China and runs Paektu Cultural Exchange, a programme that facilitates educational and sport exchanges with North Korea.
Ms Meng’s arrest has sandwiched Ottawa between Washington and Beijing as they feud over trade, cyber espionage and a raft of issues.
Mr Saint-Jacques said Mr Kovrig is going to be “a victim” of the US-China trade war.
“China wants to demonstrate to the world that it is a rival superpower to the United States and that countries have to choose to align with the US or with China,” said Mr Shaun Rein, who looked at the sticks and carrots Beijing wields in his book The War For China’s Wallet.
“The former Canadian diplomat is a pawn and he’s going to be stuck unless (Meng) is released,” he said.
Ms Meng’s arrest occurred on the same day that the US and Chinese presidents agreed at a G-20 summit to a trade war truce and a March 1 deadline to negotiate a deal.
“By getting a Canadian, it’s a power play; the US Congress won’t kick and scream. The trade talks can still go on because China has still been adhering to the agreement at the G-20 with Trump,” Mr Rein said.
US officials have not linked Ms Meng’s arrest to the trade talks under way between China and the US.
Friends describe Mr Kovrig as a friendly, decent man who loves China.
He was based in Hong Kong for the ICG, an organisation known for its research on peaceful solutions to global conflicts.
His duties included research and analysis on foreign affairs and security issues facing countries in the region, especially on the Korean peninsula.
He wrote op-eds and gave frequent interviews on the issues.
But ICG closed its office in China’s capital, as Beijing rolled out a more restrictive law that took effect in early 2017 to better control foreign non-governmental organisations (NGOs) operating in the country.
China’s foreign ministry spokesman Lu Kang said on Wednesday that ICG was not registered in China and its employees would be “in violation” of the law if they engage in activities in the country.
Mr Kovrig served as political officer at the Canadian embassy from 2014 to 2016. He met dissidents and travelled to China’s restive far west Xinjiang region, Mr Saint-Jacques said.
He took an unpaid leave from the embassy because he wanted to be able to return to China, the former ambassador said.
“He is a really nice guy, soft spoken, good sense of morals,” said Dr David Zweig, a friend of Mr Kovrig’s and a fellow Canadian China watcher, noting that Mr Kovrig is well respected in the Hong Kong community.
“They’ve got their hostage and hopefully they’ll let him go very quickly,” said Dr Zweig, a professor of Chinese politics at Hong Kong University of Science and Technology.