A fourth and final guilty plea has been secured in what federal authorities have called the largest methamphetamine seizure in Minnesota history, which would have been worth millions of dollars had the cache reached the street.

Peter Martin, 35, of Minneapolis, submitted his plea Monday in federal court in Minneapolis to one count of conspiracy to distribute and possess methamphetamine.

Martin’s three cohorts pleaded guilty earlier in the case involving about 190 pounds of methamphetamine. Awaiting sentencing are Fernando Ramos-Meza, 34; Javier Lopez-Lopez, 47; and Juan D. Valdez-Mendoza, 24.

Law enforcement officers with a drug task force searched Ramos-Meza’s home in the 3600 block of N. Dupont Avenue in Minneapolis, finding five adults and three children inside. The officers found 191 pounds of meth (packaging included), a 12-gauge sawed-off pump shotgun, 1.1 ounces of tar heroin and several thousands in cash.

The case is described as the largest meth seizure in state history. Court papers show that it turned on the help of a U.S. Drug Enforcement Administration informant and surveillance footage seized from an Inver Grove Heights storage business allegedly used to warehouse drugs as part of a plot traced to Kansas City and Mexico.

Law enforcement officials estimated that if sold wholesale, the methamphetamine would have brought in about $684,000. Supply has increased over the past 10 years, when the drug could have sold for about five times that amount. When the drug is sold to users at street level, it goes for as much as $100 a gram, making the seizure worth about $7.7 million, the task force said.