He was accused of secretly advising a Chinese diplomat on how to pressure Canada to release two Canadians detained in China
The two Canadians, Michael Kovrig and Michael Spavor, were arrested in China in 2018 on espionage charges, shortly after Canada arrested Huawei executive Meng Wanzhou on a US extradition request
Kovrig and Spavor were released in 2021 after Meng reached a deferred prosecution agreement with the US and returned to China
The allegations against Dong were based on a leaked audio recording of a conversation between him and a Chinese diplomat in 2019
Dong denied any wrongdoing and said he was only trying to help the two Canadians as a concerned citizen
He said he decided to resign from the Liberal caucus to avoid becoming a distraction for the government and his colleagues
Prime Minister Justin Trudeau said he was unaware of the allegations until they were reported by the media and that he took them very seriously