William De Roo Ramirez was about halfway into hauling more than 150 pounds of meth up from Phoenix to St. Paul, a journey he had made more than a dozen times before, when he was stopped on the highway in rural Oklahoma.

According to federal criminal complaints filed Monday in Minnesota, Ramirez stood to make $20,000 on the delivery but opted to cooperate with authorities, setting in motion a series of arrests across the metro late last week.

Before agreeing to lead DEA agents to customers in the Twin Cities, according to a DEA agent's affidavit, Ramirez said he had been responsible for hauling large loads of meth up north for Mexican drug trafficking organizations. On Monday, federal prosecutors charged Ramirez, a passenger who loaned him her car, and two alleged Twin Cities traffickers after Ramirez aided in at least two controlled purchases in Minneapolis and St. Paul on Friday.

According to the agent, Ramirez and Maria Salas-Sanchez were first stopped in Guymon, Okla., for a license violation last Thursday. Drug investigators found 151.8 pounds of methamphetamine and a semiautomatic handgun inside a 2017 Toyota Camry that Salas-Sanchez supplied Ramirez for the drive.

DEA agents in the Twin Cities replaced the actual methamphetamine bundles with sham packages that Ramirez agreed to deliver to customers while under surveillance. Prosecutors have charged at least two buyers who met with Ramirez on Friday.

Agents arrested Miguel Morales after he retrieved 40 bundles from Ramirez in a Minneapolis parking lot. Morales later told investigators that he "picked up some [expletive] from a guy that they sent me to pick up" but that he thought he would be picking up cocaine. Morales said he would be storing the drugs inside a Minneapolis home until being told to deliver to several locations and that a man named "Armando" aka "Brodie" twice paid him $10,000 to pick up narcotics.

Miguel Angel Alcaraz Ranjel, arrested after what he thought would be a 20-pound meth deal with Ramirez in St. Paul, told agents that a man named "Marro" who lived in Mexico told him where to meet Ramirez for the deal. Alcarez Ranjel said he expected between $2,000 and $3,000 for picking up and delivering the methamphetamine to another man he knew as "Guerro."

Ramirez and Salas-Sanchez were charged with aiding and abetting the possession with intent to distribute methamphetamine. Both Morales and Alcaraz Ranjel received similar charges. Neither of the four had an attorney listed for them in federal court records.

According to the complaints, Ramirez told investigators that he has driven from Phoenix to St. Paul more than 15 times and last shipped between 60 to 70 pounds of methamphetamine in December. He said he paid Salas-Sanchez for providing the vehicle and that he had expected to be paid $20,000 for this latest delivery.

Stephen Montemayor • 612-673-1755 Twitter: @smontemayor