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.
More top news
Could be worse this Bank Holiday! Fine start on Sunday, hazy sun later. Cloudy start Monday, rain later. Winds easing
The north of England certainly sees the best of the Bank Holiday weather, lots of dry conditions, but still the risk of showers at times
A woman was told she had breast cancer, just months after a scan at a Lancashire hospital had given her the all clear.