Canada says a second person has been questioned by Chinese authorities, further heightening tensions between the two countries after the arrest of a former diplomat in Beijing and the detention of a Huawei Technologies Co. executive in Vancouver.

The second person reached out to the Canadian government after being questioned by Chinese officials, Foreign Minister Chrystia Freeland said, adding Canada has since lost contact with the person.

“We haven’t been able to make contact with him since he let us know about this,” Freeland told reporters Wednesday in Ottawa. “We are working very hard to ascertain his whereabouts and we have also raised this case with Chinese authorities.”

The Globe and Mail identified the man as Michael Spavor, a Canadian whose company brings tourists and hockey players into North Korea. He gained fame for helping arrange a visit to Pyongyang by former NBA player Dennis Rodman, and he met North Korean leader Kim Jong Un on that trip, the newspaper reported.

Calls to both of Spavor’s contact numbers in China, as well as his North Korean number, went straight to voicemail. Canada’s foreign affairs department didn’t immediately respond after regular business hours to a request to confirm the identity of the second person.

Canada-China relations are being tested after China’s spy agency detained former Canadian diplomat Michael Kovrig, on leave from the foreign service, Monday in Beijing. The arrest came nine days after Canada arrested Huawei Chief Financial Officer Meng Wanzhou at the request of U.S. authorities.

Related: China Implies Detained Canadian Michael Kovrig Was Engaged in ‘Illegal’ Work