The federal RCMP suspended the program last week after learning of allegations against the force, including racism and abuse of authority.
The allegations first surfaced when the Justice Department issued a report in mid-December outlining its findings from a civil rights violations probe into the Maricopa County Sheriff's Office.
The probe found "reasonable cause to believe" the force engages in "unconstitutional policing," including racial profiling, retaliating against people who criticized its policies and disregarding basic legal obligations.
It suggested Latinos were being unlawfully stopped, detained and arrested, and that inmates who don't speak English were punished for failing to understand commands and refused basic services.
Maricopa County has coupled with national RCMP for years, with county officers teaching in Canada and Canadian RCMP officers — including those from municipal and provincial forces — doing "field certification" at the county's jail.
That field work involved having police officers test their drug recognition skills on prisoners who had been stopped for allegedly driving while under the influence of drugs.
A letter from the RCMP sent on Friday shows Deputy Commissioner Doug Lang decided to immediately suspend the program just days after being alerted to the report by the B.C. Civil Liberties Association.
"I would like to extend our appreciation to you and your organization for bringing this matter to our attention," says the letter from Supt. Brian Simpson to association Executive Director David Eby.
The letter states it is the RCMP's understanding that prisoners volunteered to participate in the field work portion of the training. It says they were not given preferential treatment or remunerated for doing so, and only interacted with instructors of the training program.
"Having said that, the U.S. Department of Justice report does bring this into question," says Simpson in the letter.
A spokesperson for the Maricopa Sheriff's Office could not be immediately reached for comment.
Eby said he's pleased with the RCMP's swift action against the "rogue" force, and thinks it is appropriate for the Mounties to cast doubt on the adequacy of the training program.
"There's a serious question about why those prisoners were in the lockup, given the arresting policies and procedures of this police force," he said in an interview on Sunday. "Were the prisoners consenting to that? How did they end up in the lockup? Would they just round up a whole bunch of people during a training program?"
Eby called on the RCMP to conduct a retroactive review to ascertain whether the training officers have received can be relied upon. He also noted there may be future implications in criminal court proceedings.
He added he hopes the scenario awakens the RCMP to the risks of relying on American police as service providers.
"I think the American policing context is very different than the Canadian policing context and that Canadians need to rely on Canadian societal norms and Canadian constitutional and legal norms," he said.
Calls for comment to RCMP Headquarters in Ottawa Sunday were not immediately returned.
According to the B.C. Civil Liberties Association, the RCMP had planned six three-week-long workshops between April and March 2013 for approximately 200 RCMP in Maricopa County.
The county trains 85 per cent of all drug-recognition experts in North America.