The RCMP had no data to back up their claims that medical marijuana grow operations under Canada's old licensing system were inherently dangerous to producers and magnets for violent thieves and organized criminals, an expert told the Federal Court Thursday.

RCMP Corporal Shane Holmquist, a supervisor on the Federal Serious Organized Crime Section's marijuana enforcement team, made headlines last year when he filed his affidavit in this case stating there was an "overwhelming temptation" for growers licensed under the old federal medical marijuana system to divert extra pot to the black market. His affidavit also stated that such producers face risks from mould, fire and electrical hazards and also attract organized crime groups because, quoting a 2005 RCMP report, "marihuana cultivation and trafficking represents the single most common (and most lucrative) activity pursued by organized crime."

Concerns about criminal activity formed part of the rationale that led Health Canada to overhaul its medical marijuana system last year to strictly license only industrial-scale production in secure commercial facilities.

Story continues below advertisement

Cpl. Holmquist was testifying at a case involving the constitutional challenge by four plaintiffs alleging that their Section 7 Charter rights were violated when the federal government enacted the new system that outlawed their personal grow operations. They say they can't afford marijuana under the new system, which also doesn't give them control over the specific strains they use. They are asking the court to force the government to allow patients to grow their own marijuana, which many licensed Canadians kept doing after the Federal Court judge granted an injunction to the four plaintiffs in March of last year pending the outcome of this legal challenge.

During cross examination Thursday, Cpl. Holmquist said the RCMP had no data on how many of the roughly 28,000 people authorized to grow their own pot, or have another licensee do it for them, were subverting or abusing the old system. He said he had been a part of more than 100 investigations into licensed producers, but had not collected statistical data on any of them.

John Conroy, lead counsel for the four plaintiffs fighting to keep growing their own medical marijuana, said the evidence the RCMP relied on was "very thin" and may implicate no more than 300 licensed producers that are abusing the system in such ways.

"They've done certainly no social science research, comparative analysis, random sampling and so on, as counsel has been demonstrating," Mr. Conroy said during the lunch break. "The substantial majority of these people, I'm talking 99.9 per cent or 98 per cent, were doing everything properly and legally.

"I'm not surprised because most people who are trying to do something for themselves try to do it right, try to do it properly and not cause harm to themselves or anybody else."

A 2009 RCMP review found 40 cases of licence holders selling excess marijuana for profit, and Cpl. Holmquist's affidavit stated that there were four violent thefts at licensed B.C. producers in 2009 and 11 the following year.

His affidavit stated that between 2003 and 2013, there were 14 homicides related to grow-op thefts in B.C.'s Lower Mainland, but during cross-examination Cpl. Holmquist said there was no evidence that any of those were at licensed production facilities.

Story continues below advertisement

Cpl. Holmquist said it is very difficult to know how deeply organized criminals have penetrated the medical marijuana production system because of the inherent secrecy surrounding most of these groups.

Mr. Conroy said there is no doubt some people hid behind licences to abuse the system for profit by selling to the black market and that some organized crime groups may have "compromised patients," but the vast majority did not abuse the old system.

He said most of the RCMP's concerns around fire and electrical safety risks at the licensed grow operations are "greatly exaggerated" and remedial actions can be enforced safely by Health Canada.

For example, he said licensees growing in their homes could be forced to buy $3,000 "bloom boxes," which encase the crop and protect it from fire, electrical safety risks, humidity and odour.

The trial is expected to last into May and next week legal experts on medical marijuana reform from the United States, the Netherlands and Israel are slated to testify.