The FBI has seized $28.5 million worth of bitcoins from the alleged mastermind behind the online drug market Silk Road, according to a report from Forbes. An unnamed FBI official reportedly tells Forbes that the agency seized a collection of 144,000 bitcoins that belonged to Ross Ulbricht, who earlier this month was arrested and charged with being the owner of Silk Road. This is reportedly the largest seizure of bitcoin — the semi-anonymous digital currency — ever made, and is said to have been completed earlier today.

Other stashes of bitcoin related to Silk Road may still remain, however. Forbes reports that a separate collection of 111,000 bitcoins — or about $22 million — has been identified as potentially belonging to Ulbricht, but that the FBI appears not to have taken it just yet. That may be because the FBI hasn't gained the necessary key to unlock it, or simply because the account isn't under suspicion.