Five people have been arrested in Northumberland, Tyneside and Wearside after police discovered a coach firm was being operated without a licence.
Two houses in Cramlington were searched following the discovery.
Officers found £100,000, counterfeit clothing, a taser and a large quantity of Viagra.
Four men and a woman were arrested at addresses in Sunderland, Newcastle, Cramlington and Seaton Burn on suspicion of money laundering.
Police have said they will now apply to seize money, vehicles, houses and commercial properties valued at about £1.5m in connection with the arrests.
Det Ch Insp Jim Mcall, of the Economic Crime Unit, said: "The Proceeds of Crime Act allows the police to tackle suspected criminals using unconventional methods and hit them where it hurts by taking their wealth from them.
"In this case we are investigating individuals who are suspected of running a commercial enterprise whilst not being legitimately licensed to do so."