PORTLAND – The alleged leader of a drug ring that smuggled millions of dollars’ worth of marijuana, LSD and Ecstasy across the border from Canada is expected to plead guilty to charges that could send him to prison for life.

Robert Shimek, 29, is one of the only people ever charged in Maine for running a continuing criminal enterprise, a federal charge typically leveled against gang lords and organized crime bosses.

Shimek pleaded innocent in July, but is scheduled to change his plea to guilty in U.S. District Court today. He faces 20 years to life.

U.S. Marshals had tracked Shimek for several years, and prosecutors said there is abundant evidence against him. Shimek has agreed to change his plea and forgo a trial without any agreement to limit his sentence, said Assistant U.S. Attorney Jonathan Toof.

“This is the first time in at least recent memory that anybody has pleaded guilty to this charge,” Toof said.

Shimek’s lawyer, Leonard Sharon, did not return phone calls Wednesday. Shimek, who is being held at Cumberland County Jail, could not be contacted directly because of his status as a federal inmate, jail officials said.

The guilty plea, if approved by Judge Gene Carter, would virtually end an international case that began in 1998 when Westbrook police responded to a complaint about the aroma of marijuana coming from a room at the Super 8 Motel.

The officers found about 34 pounds of marijuana and three guns hidden above the bathroom ceiling tiles. They also found several telephone and address books that led federal agents to a drug-dealing operation that Shimek allegedly started in 1996.

Shimek and others first were based in Montreal, then just outside Quebec City. Carrying backpacks, and in at least one case armed with an Uzi machine gun and other weapons, they would walk the drugs into Maine across isolated, unguarded portions of the Canadian border, according to court documents.

Once in Maine, a car would meet the hikers and bring them to a cabin in Caribou, where members of the group stored, prepared and packaged the drugs, some of which were distributed at concerts by the bands Phish and Widespread Panic, according to court documents.

“Most often you look at Maine as not very big on the scale of drug organizations. But here’s a guy who was using it as a conduit for his enterprise,” said Roy McKinney, head of the Maine Drug Enforcement Agency. The state agency assisted federal drug agents who worked with the U.S. Marshals Service and other American and Canadian agencies to track Shimek down.