Police have scooped over $13 million worth of marijuana away from a high-level distribution network they say is operating in Calgary and backyard communities.

Over a dozen Calgary homes were raided Wednesday and Thursday, bringing the number of illegal pot plants seized in the past two months up to 8,675. Half of them were caught growing $1 million worth of plants.

Police say the busts are connected.

Homes in Irricana and Balzac were also targeted recently as part of the undercover operation that began seven months ago.

The drug plants were destined for Canadian and U.S. markets.

"This was going to a large market, it was too much for use locally," said RCMP spokesman Sgt. Patrick Webb.

"They are always connected. This is a business thing, these are not mom-and-pop things selling to the neighbourhood. This is a high-level distribution network."

Nine people are facing charges resulting from the undercover investigation led by the Southern Alberta Marijuana Investigative Team, a joint-forces operation between RCMP and Calgary police.

"We're getting arrests and individuals charged, but we're still trying to get the upper-level management people," said Webb.

Thanh Vinh Huynh, 28, Minh Tan Mach, 27, Nghia Thien Huynh, 41, and Huong Ngoc Cao, 35, all of Calgary, were charged with possession for the purpose of trafficking marijuana, cultivation of marijuana and theft of electricity.