A key witness involved in the arrest of Huawei Chief Financial Officer Meng Wanzhou two years ago has decided not to testify in a Canadian court.
Meng arrived back in the British Columbia Supreme Court on Monday as her US extradition hearing resumed.
Her lawyers are fighting to establish that Meng's rights were violated during the events leading up to her arrest.
They called the refusal of a senior Canadian police officer to testify "concerning."
Meng, 48, was arrested in December 2018 at Vancouver International Airport by Canadian police on a warrant from the United States.
She is accused of misleading HSBC about Huawei Technologies Co Ltd's business dealings in Iran, causing the bank to break US sanctions.
Meng has said she is innocent and is fighting the extradition from under house arrest in Vancouver, where she owns a home in one of Canada's most expensive neighbourhoods.
On Monday defense lawyer Richard Peck told the court one of the key witnesses, Staff Sergeant Ben Chang with the Royal Canadian Mounted Police, would not be testifying.
According to court documents, Chang, who is now retired, allegedly sent details of Meng's electronic devices to the FBI. He denied the allegation in an affidavit submitted to courts.
Peck told the court Chang's refusal to testify is "a matter that will be of some concern," adding that "there may be any number of consequences from his refusal to testify".
Monday kicks off 10 days of testimony that are a continuation of hearings set to wrap up in early November but ran overtime.
Lawyers for both Meng and the Canadian government will spend the week cross-examining Canadian law enforcement officers and border officials involved in the initial investigation and arrest.
Meng's lawyers are fighting to get her extradition dismissed on the basis of alleged abuses of process, arguing they constitute violations of her civil rights laid out in Canada's Charter of Rights and Freedoms.
In the first week of hearings, prosecutors for the Canadian government tried to prove Meng's arrest was by the book and lapses in due process should not impact the validity of her extradition.
The defence has argued CBSA officers should have delayed their examination of Meng and turned her over immediately to the RCMP, and doing otherwise violated her rights.
On Monday, prosecutor Diba Majzub asked CBSA officer Sanjit Dhillon, who was involved with examining Meng, whether it was common for border officers to delay customs examination on non-Canadians.
"I've never seen a case where the examination was delayed in any way," Dhillon said.
The extradition hearings are scheduled to wrap up in April, though the potential for appeals mean the case could drag on for years.