Chinese authorities have indicted a Canadian man on spying and stealing state secret charges nearly a year and a half after detaining him.

Authorities found clues that Kevin Garratt had accepted an assignment from Canadian intelligence to spy on China, China’s central state-run Xinhua news agency reported in a two-paragraph update late Thursday.

Mr. Garratt and his wife, Julia, were detained on Aug. 4, 2014, in Dandong, a small Chinese city on the border with North Korea, where the Christian couple ran a coffee shop and led church services.

Their detention created a diplomatic storm, with Stephen Harper, then prime minister, raising their case directly with Chinese leadership during a state visit to China in November, 2014.

Ms. Garratt was released on bail on Feb. 5, 2015.