A boy looks up as he walks past the closed coffee shop owned by Canadian couple Kevin Garratt and Julia Dawn Garratt in Dandong, Liaoning province, August 5, 2014. [Photo/Agencies]

A Canadian man has been formally detained on suspicion of stealing and prying into State secrets by the State Security Bureau of Dandong, Northeast China's Liaoning province, while his wife was granted bail, Foreign Ministry spokesman Hong Lei said on Thursday.

The authorities are dealing with the case in accordance with the law, and legal rights and interests of Kevin Garratt and his wife Julia Dawn Garratt have been maintained, Hong said at a daily press briefing.

The case is under investigation, he added.

Kevin and Julia Garratt, who ran a coffee shop on the Chinese border with the Democratic People's Republic of Korea (DPRK), were put under residential surveillance by the State Security Bureau of Dandong on Aug 4, 2014 on suspicion of engaging in activities that endanger China's national security, Hong said.

The Garratts' coffee shop has a view of traffic flowing across the Yalu River, according to The Globe & Mail. The couple also had a side business helping people plan tours there, it added.

The newspaper said the shop was named after the couple's youngest son. The couple have three children, said David Etter, an American who knew the family and had run a restaurant in another city bordering the DPRK.

He said the Garratts had lived in Dandong for at least six years.

In July, Chinese prosecutors charged British corporate investigator Peter Humphrey and his American wife, Yu Yingzeng, with illegally obtaining private information. They were detained last year following work they did for the British drug maker GlaxoSmithKline Plc.

The theft of State secrets is punishable with life in prison or the death penalty in severe cases, according to China's State secrets law.