Notorious dark web marketplace Evolution has vanished amid reports that its administrators have absconded with more than $12m in bitcoin.

Accessible only via the Tor network, the market had become the go-to online drug bazaar following the shut down of Silk Road and Operation Onymous, a pan-agency crackdown on illicit markets that seized over 400 domains in November.

Members of the darkweb community expressed concerns about Evolution's moderators – operating under the handles 'Kimble' and 'Verto' – who were delayed responding to and processing withdrawal requests.

Reddit's Evolution discussion page was also awash with claims that the site's administrators had blamed the delays on a backlog of withdrawals, reassuring worried vendors that the issue would be resolved within 24 hours.

However, the Evolution marketplace and its user discussion forum went offline shortly after, indicating the possibility that the administrators had taken the money and dissapeared.

Reddit user NSWGreat, who previously claimed to handle the site's public relations, said: "Evolution can officially be put on the Wall of Shame. Verto and Kimble have [expletive] us all."