MINNEAPOLIS — Twenty people have been charged in a drug ring that authorities say has ties to Mexican drug cartels and is responsible for selling massive amounts of methamphetamine in the Minneapolis area, greater Minnesota and western Wisconsin.

Hennepin County Attorney Mike Freeman announced the charges Friday. He said a wiretap was critical in the eight-month investigation, in which authorities seized nearly 17 pounds of meth with a street value of over a half-million dollars.

“When you take that much out, you make a dent in the market,” Freeman said.

Authorities said the defendants were targeting the Hmong community. In addition to seizing drugs and cash, authorities also recovered four firearms and armor-piercing ammunition.

“It has made St. Paul, Minneapolis, the east and west metro, a safer place,” said St. Paul Police Chief Tom Smith.

The investigation is ongoing, but authorities believe much of the methamphetamine was produced in Mexico and came to Minnesota through California. A criminal complaint said some of the defendants had ties to the La Familia Michoacana Mexican drug cartel and had direct conversations with suppliers in Mexico.

Freeman said the investigation began when an informant went to St. Paul police about meth sales. The FBI became involved through its Safe Streets Task Force, which investigates gangs as organized criminal enterprises and targets the worst offenders. Multiple agencies were involved.

The criminal complaint outlines phone conversations in which authorities overheard defendants talking about drug sales, some of which were made in hotels in Brooklyn Center, St. Paul and Shakopee. In one conversation, a defendant from Eau Claire, Wis., talked about coming to the Twin Cities with money so he could get more drugs because his supply was out, the complaint said.

All 20 defendants are charged with conspiracy to commit a controlled substance crime, Freeman said. The defendants had a variety of roles, from dealing directly with suppliers to distributing the meth on the street.

According to the criminal complaint, one defendant was pulled over by the Minnesota State Patrol in Lakeville, just two days after authorities said he met with a drug supplier in California. Authorities obtained a search warrant for the car he was driving, and found a hidden compartment under the back seat — filled with 9.6 pounds of meth.

St. Paul police Commander Dave Korus, who is a member of the Safe Streets Task Force, said generally speaking, dealers will stash meth in a car, then drive it cross country. When the car arrives in Minnesota, for example, it’s taken apart, the drugs are distributed, and the car is then filled with cash and driven back to the supplier.

Korus said some of the meth seized in this case was of high quality.