A man accused of helping run a million-dollar methamphetamine lab out of Fulton and DeKalb counties became the sixth to plead guilty to federal charges, according to the U.S. Attorney’s Office.

Santana Cardenas, 41, of Mexico, was the final defendant to enter a guilty plea after officials accused him of conspiring to convert more than 400 pounds of liquid meth into crystal meth, according to U.S. Attorney BJay Pak.

Fredrico Pacheco-Romero, 27, Carlos Martinez, 24, Jorge Mendoza-Perez, 50, Victor Manuel Sanchez, 21, and Eduardo Lopez, 26, previously pleaded guilty to conspiracy to possess methamphetamine with intent to distribute.

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The charges stemmed from a months-long investigation by the Drug Enforcement Administration that connected the local group to a Mexico-based drug cartel. Pak said Pacheco-Romero and Martinez were the local leaders of the group.

More than a quarter of a ton of meth, valued at nearly $1.7 million, was discovered during the investigation, AJC.com previously reported. The group used homes in Milton and Ellenwood.

An indictment accused the men of conspiring to “knowingly and intentionally possess with intent to distribute a controlled substance.”

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Agents learned that a shipment of liquid meth was heading to the Atlanta area in February 2019. On Feb. 9, DEA agents obtained warrants and searched half a dozen properties the group was using, according to Pak.

During the searches, authorities found active conversion labs and meth, Pak said. Officials searching a home off Mountain Road in Milton discovered 300 pounds of meth, and a bust at a home on Hearn Road in Ellenwood yielded another 120 pounds.

Agents also found hundreds of thousands of dollars in cash, multiple cellphones, drug ledgers and guns.

The six defendants are each scheduled to appear in federal court for sentencing in early 2020.

In other news: 

The bridge is being replaced to widen I-85 between I-985 and State Route 53 in Jackson County.