Four men arrested after a historic meth bust in Minneapolis last month now face federal drug and gun charges, according to a new criminal complaint that raised the total of meth seized to 191 pounds.

The case is described as the largest meth seizure in state history; newly filed court papers show that it turned on the help of a DEA informant and surveillance footage seized from an Inver Grove Heights storage business allegedly used to warehouse drugs.

The U.S. attorney’s office on Friday filed a criminal complaint charging Javier Lopez-Lopez, Juan Daniel Valdez-Mendoza, Peter Martin and Fernando Ramos-Meza with conspiring to possess and distribute meth in a plot with ties to Mexico and Kansas City. Martin is also charged with illegally possessing a sawed-off shotgun.

According to a Homeland Security Investigations agent’s affidavit, investigators seized 191 pounds of meth from Ramos-Meza’s north Minneapolis home on Sept. 11, the same day police reviewed footage that showed the men hauling several large boxes from a storage business to be taken to the home.

Most of the meth was found in a pair of Home Depot moving boxes and a speaker box that Ramos-Meza allegedly later told officers was unloaded from a large passenger bus that was also captured on the storage business’ security camera earlier that day.

All four men spoke with investigators after the raid in the 3600 block of Dupont Avenue N. Ramos-Meza, 33, said Lopez-Lopez, 46, and Valdez-Mendoza, 23, recently arrived from a trip to Kansas City and identified Lopez-Lopez as a person in contact with others to arrange drug delivery.

Martin, 34, allegedly admitted to owning the shotgun, which officers found inside an overturned refrigerator in a bedroom in which Martin had been staying. Martin told police he bought the shotgun to protect his family and said Lopez-Lopez was responsible for bringing meth to Minneapolis, where Ramos-Meza oversaw sales of the drug.

Valdez-Mendoza meanwhile identified Ramos-Meza as “the person who has all the connections in Mexico.” Valdez-Mendoza said he was from Mexico “where the cartels are very active” and said he feared for the safety of his family.

State and federal investigators are seizing more meth in or bound for Minnesota from Mexico than at any point, including about 1,500 pounds last year — or about four times the total retrieved five years ago. Earlier estimates placed the total of meth seized from Ramos-Meza’s home about 170 pounds. The new total eclipses a January seizure from a courier stopped in Oklahoma as he drove from Arizona to Minnesota, where he later led agents to multiple customers.

Meanwhile, a recent federal civil forfeiture proceeding shed further light on the investigation, which authorities have said started in January. The government is seeking to keep $24,400 taken from Jesus Ivan Herrera during an April traffic stop in southern Minnesota. According to Assistant U.S. Attorney Craig Baune, an informant working for the U.S. Drug Enforcement Administration tipped investigators that Herrera would be traveling back to the Minneapolis area from Missouri and that he would have a large amount of cash in drug proceeds.

Baune wrote that a GPS tracker previously placed on Herrera’s car linked him to multiple trips to Ramos-Meza’s home and that the informant said Herrera had been instructed to go that address.