Nearly 20 people have been killed since 2006 in Sonoma and Mendocino County, California as the result of the illegal marijuana trade. These statistics have caused some growing concerns with the local authorities that say pot is at the root of the violence taking place on the North Coast.

According to Sonoma County Sheriff Steve Freitas, while area homicides are a rarity, drug related homicides, specifically those where marijuana sales are a factor, are becoming increasingly more widespread in much of Northern California. Police records indicate that of the 18 people murdered, nine of them were targets of robberies.

Most recently, three men, including 24-year-old Raleigh Butler of Sonoma County, 42-year-old Todd Klarkowski of Boulder, Colorado; and 46-year-old Richard Lewin of Huntington, New York were brutally murdered by three men, currently standing trial in the Sonoma County Superior Court, so they could gain control of roughly 70 pounds of weed -- valued at just under $200,000.

A similar incident took place a couple years ago after four men arranged to purchase about 20 pounds of marijuana from 33-year-old Jose Manuel DeJesus, but instead shot DeJesus outside a local market and stole the weed.

Police also say that it’s not just the drug dealers that are killing each other; those with home-grow facilities are often the target of similar violence. In 2006, 31-year-old Andre Grant – a medical marijuana patient -- was murdered for 25 pot plants he had growing in his garage. Authorities still have not been able to identify any suspects.

Still, while much of the drug-related violence stems from theft, Mendocino County Sheriff Tom Allman attributes a large percentage of the brutality to the complex relationships between growers and sellers. "The violence we see in most marijuana cases deals with the business portion of marijuana cultivation as well as sales. There's a lot of money there," he said.

Mike Sena, director of the Northern California High Intensity Drug Trafficking Area says that a 2010 state report estimates the marijuana market in Northern California is worth $14 billion per year.

Interestingly, Sena says that along with the drug related violence, comes a substantial cash flow that stimulates the local economy: inflating everything from hotel rooms to the cost of land.

Mike Adams writes for Playboy's The Smoking Jacket, BroBible and Hustler Magazine. Follow him: @adamssoup; facebook.com/mikeadams73.