Eight people have been charged following the drug raids across Greater Manchester.
They will all appear at Bolton magistrates' court today charged with conspiracy to supply drugs.
On Wednesday, officers raided eleven addresses as part of an operation to disrupt the activities of a suspected organised crime group.
Warrants were executed across the Bolton, Bury, north Manchester and Salford areas of Greater Manchester and a number of properties.
Officers were investigating the sale of approximately 313 kilograms of mephedrone with the street value of £3.8 million through an online website, which was run from a unit in Bolton.
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Greater Manchester Police said "inquiries are ongoing to fully understand the circumstances of the incident."
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