A multi-million-dollar synthetic marijuana operation authorities say was run by a state prison inmate resulted in six arrests in Berks County.

Last Thursday, six people, along with $2.4 million in cash and more than 300 pounds of drug-making materials were picked up in an early-morning raid in Berks County by 70 law enforcement officers, said Michael Gombar, chief Berks County detective. The raid was conducted at six homes, a garage and two storage units.

Those charged are believed to be part of a close-knit organization led by Eric Cintron, who was arrested in August 2013 and is serving a state prison term, Gombar said. Detectives say he continued the drug operation after his arrest, even while in prison.

Last September, Homeland Security investigators learned suspicious packages were being shipped to the Reading are that contained FUB-AMB, which is a controlled substance used to make synthetic marijuana, Gombar said.

The investigation revealed actors were shipping the drugs here from China, and they were used to make thousands of points of synthetic marijuana for distribution in Berks County and beyond, Gombar said.

"The arrests and drug seizures that resulted from this collaborative investigation deal a serious blow to a large scale drug trafficking ring that pumped dangerous synthetic narcotics into our communities. " said William Walker, acting deputy special agent in charge of HSI Philadelphia. He said the agency will continue working with Berks County and Reading law enforcement officials to "purge the streets of dangerous criminals who import and distribute narcotics in our communities."

Seized were:

12 kilos of FUB-AMB used to make K2.

300 pounds of Damiana Leaf used to manufacture K2.

Four one-gallon canisters of acetone used to make K.2

Four handguns w/ magazine and ammunition.

About $2.4 million dollars, believed to be drug sale proceeds.

14 vehicles use by the drug organization for the distribution of synthetic marijuana.

A money counter

Numerous cell phones

A security monitor and camera, and night vision binoculars.

Numerous documents and ID pertaining to the drug suspects.

Drug-related paraphernalia associated with the manufacturing and distribution of synthetic marijuana.

Charged today was Eric Cintron, 36, now in state prison.

Charged March 23 and placed in Berks County prison on $1 million bail were:

Edwin Mendez, 34, of the 500 block of Lancaster Avenue, Reading.

Jose Cintron, 38, of the 200 block of Endlich Avenue, Mount Penn.

Miguel Gomez, 56, of the 1200 block of Perkiomen Avenue, Reading.

Joel Solis, 34, of the 300 block of Hollenbach Street, Reading.

Also, Destiny Plaza, 28, of the 500 block of Lancaster Avenue, Reading, was arrested Saturday and was released from prison on $250,000 bail.

More accused 'street level' dealers faces charges after drug sweep