Police believe they have uncovered the first website in the UK allegedly designed to sell illegal drugs over the internet.
Two men and a woman were arrested and were being interviewed on Monday following claims they had run an internet site which is thought to have supplied cannabis through the post.
Detectives believe customers could order drugs through a password-protected website and were then posted their orders.
A 37-year old man and a 33-year old woman both from Wheathampstead, Hertfordshire, and a 35-year old man from Brighton, Sussex, were arrested.
Warrants were executed at three addresses by Hertfordshire and Sussex police forces with the aid of the National Hi-Tech Crime Unit (NHTCU).
Four computers were seized.
It is alleged that an estimated £500,000 passed through bank accounts associated with the website.
The accounts have now been frozen.
Matt Cornish, of Hertfordshire Police said: "We believe this may be the first case of its kind in the country."