Ontario police have seen a 250 percent increase in indoor pot operations.

TORONTO – On the street it's called Northern Lights, Ontario Hydro, and B.C. bud. It's one of Canada's biggest agricultural exports - a potent form of marijuana cultivated in sprawling "grow houses," worth an estimated US$4 billion to $7 billion annually. Much of it is smuggled into the US.

Once hidden in farming communities and well-heeled suburbs, grow operations - indoor nurseries with high-tech lighting and temperature controls - have been thrust into the national spotlight. Thursday Canada buried four young Royal Canadian Mounted Police officers who were killed during a bust in rural Alberta March 3.

The Alberta grow house was just one of thousands across Canada. Here in Ontario, police say indoor pot operations have risen 250 percent in the past four years. And Vancouver is home to some 7,000 "grow ops" at any time, police say.

The tragedy - the deadliest incident for Canada's national police force in 120 years - has ignited debate as Canadians begin to question whether liberal attitudes toward marijuana and lenient laws enacted over the past two decades have contributed to the drug boom.

"It's really got people talking about the problem," says Marc Pinault, staff sergeant with the Ottawa Police Service's drug unit. "It's pretty clear that we produce a pile of pot, and it's really good stuff. I don't know that that's something we should be really proud of."

Drugs moving east

British Columbia has long been the hub of sophisticated, high-tech nurseries capable of producing pot with nearly 30 times the kick of what was found on the street a decade ago, according to the Drug Enforcement Agency. Sergeant Pinault says the increasing numbers of massive growing operations - once largely the preserve of Asian gangs and bikers on the West Coast - indicate the problem is moving East into provinces like Ontario and Quebec.

Tom Stamatakis, a Vancouver police officer and a member of the Canadian Professional Police Association, says criminals across the country are modeling their operations after those found in and around Vancouver.

For example, he says, grow houses are increasingly found in upscale areas of the city as criminals ply their trade behind picket fences and a facade of respectability. Inside, they're a hotbed of danger - rigged with booby traps to ward off intruders and noxious chemical compounds that pose serious health threats.

But those aren't the only perils. DEA special agent Rodney Benson of Seattle says recent busts have also netted a pile of automatic weapons and explosive devices.

"We're definitely seeing more violence," explains Mr. Benson, who recently oversaw a year long, cross- border sting called Operation Hockey Bag, in which investigators charged 22 people and seized more than 400 lbs. of marijuana, along with $3.4 million and a dozen firearms. "It's not just weapons - it's what we're seeing from the organization. They rule and intimidate from within."

RCMP investigators are still sifting through the evidence, trying to find out what led to the killing of the four officers last week. The incident began as an attempt to repossess a pickup truck but ballooned into a larger investigation after the marijuana growing operation was discovered. The gunman, Jim Roszko, killed the officers and later turned a high-powered, semiautomatic weapon on himself.

Canadian officials stress that it was an isolated act of extreme violence - and they hope to keep it that way. Many, like Mr. Stamatakis of Vancouver, say that Canadian lawmakers are too lenient in meting out penalties for those involved in growing operations contributing to the drug explosion.

"When even the outgoing prime minister [Jean Chrétien] makes a flippant comment like, 'What's the big deal about marijuana? I've probably had a few puffs myself.' That sends the wrong message to the community and the courts," Stamatakis says.

Softer laws for using, harder for selling

There has been a major push to decriminalize marijuana across the country in recent years. Canada was the first country to regulate its medicinal use, in 1999. However, while the government has recently moved to introduce softer penalties for possession, penalties for growers could get stiffer. A marijuana bill, reintroduced in November, advocates that possession of up to 15 grams would be punishable by fines of C$100 to C$150 ($85 to $125), but would no longer lead to a criminal record.

For growers, those caught with more than three plants, face up to five years in jail, or 18 months plus a C$25,000 ($20,700) fine. Those caught with more than 25 plants could face 10 years in jail, while the bill provides a maximum sentence of up to 14 years for operations with more than 50 plants.

Last week, Public Safety Minister Anne McLellan issued a warning in the wake of the shootings, telling judges that they will be forced to explain their decisions in writing if jail terms are not imposed on those who grow plants. Under Canadian laws, criminals face a maximum seven-year jail term. In practice, however, many people convicted of growing marijuana receive sentences of little more than a few months, police say.

Criminologist Patrick Parnaby says the events of last week are likely to lead to stiffer penalties. When something like narcotics is intimately tied to violence, there is going to be a powerful public backlash, says the associate professor at the University of Guelph in Ontario. "Stricter laws will make the public feel a whole lot better," he says.

But many users pushing for decriminalization couldn't disagree more. Blair Longley, leader of the federal Marijuana Party, says legalization would wipe out criminal enterprises across the country.

"They've just used this [the Alberta shootings] as an excuse to crack down and enforce outdated laws," says Mr. Longley. "In reality, liberalizing the laws would mean you would get rid of almost all the profits and, therefore, all the crime."