A B.C. man who ran a helicopter-based drug-smuggling ring into Washington state has pleaded guilty to a conspiracy charge, after fighting his extradition to the U.S. for much of the past decade.

Colin Martin, formerly of Malakwa, B.C., entered the plea on Thursday in U.S. District Court in Seattle.

The 46-year-old admitted he led a drug ring that sent helicopters with marijuana and MDMA — also known as ecstasy — to remote landing pads in Washington state. The drugs would be exchanged for cocaine and cash, which were flown back up to Canada.

U.S. authorities seized 340 kilograms of marijuana, 83 kilograms of cocaine and 240,000 ecstasy tablets when they broke up the operation in 2009 — and then-U.S. attorney Jeff Sullivan said there was likely more.

"This organization has been responsible for a much larger amount of drugs than what we were able to seize," he said.

The drugs were valued between $10 million and $15 million. A significant amount of cash, guns, two helicopters and other equipment was also seized.

Associates

Six people, including Martin, were charged that year.

Two of Martin's alleged associates have since died, along with one of their girlfriends.

Sam Brown hanged himself in a U.S. prison weeks after the bust. He'd been arrested after flying a helicopter loaded with drugs into a federal law enforcement trap.

Jeremy Snow, 33, and his girlfriend Tiffany Goruk, 30, were killed in West Kelowna, B.C., in 2013. Snow had finished serving time in the U.S. in connection with the same drug bust.

Jeremy Snow and girlfriend Tiffany Goruk were found dead in West Kelowna in 2013. (Facebook)

Martin, who has six children, left school in eighth grade to go to work as a logger. In a 2009 interview, he said he became involved in the drug trade after he saw his best friend killed in a logging accident and the local salvage timber industry collapsed.

He first came to the attention of American authorities in the late 1990s, when he was charged for a drug smuggling operation that relied on airplanes.

Martin never responded to those charges and was never extradited, but he was convicted in Canada based on the same conduct. He was sentenced to two and a half years in prison in 2007.

He continued smuggling while he appealed by leasing or buying helicopters through a company called Gorge Timber.

The Supreme Court of Canada rejected his arguments against extradition in December after years of fighting.

Martin faces five to 40 years in prison, but the U.S. Attorney's Office said it would recommend no more than 10 years.

Sentencing is set for June.

With files from the Associated Press