The Communist State's Foreign Ministry has claimed Kevin Garratt and Julia Dawn Garratt's 'actions' had harmed China's state security activities.
The couple have been living in China since 1984 and are understood to have had a long-held passion for humanitarian work.
According to the Wall Street Journal, in an interview, one of the couple's sons, who lives in Vancouver, said his parents' interest in North Korea drew them to the gritty northeast border town of Dandong, where they lived and ran a coffee shop.
"I just find this whole situation so crazy when pretty much all my parents have done for the last 30 years is dedicate their lives to helping people in China," said Simeon Garratt, 27 years old. "My best guess is honestly some sort of miscommunication or misunderstanding and it led to my parents paying the price."
He said the last anyone heard from his parents was around 6:30 p.m. local time Monday when they were heading out for dinner. Chinese authorities later informed Canada's embassy in Beijing of the investigation, he said.
Simeon Garratt said his parents had lived in Dandong since around 2008, and his brother, Peter, was still living there and had received a Chinese government scholarship for his studies. Simeon Garratt said his brother remained in Dandong, and that the investigation into their parents didn't appear to have any relation to him.
Moving to the border town between China and North Korea appealed to the Garratts because they wanted to play a role in providing aid to North Koreans, according to David Wells, a church leader who knows the family.