For two and a half years, the black market bazaar known as the Silk Road tempted thousands of drug dealers and customers with promises of anonymous commerce—as well as at least two corrupt law enforcement agents who tried to profit from the dark-web-based business they were meant to be investigating. Now the defense team of the site's creator says it's found signs of a third rogue cop tied to the Silk Road's drug money. And this one, they say, remains at large.

In a press conference today, lawyers representing Silk Road's convicted founder, Ross Ulbricht, announced that they've dug up private chat logs from the site's user forum that shed light on a mysterious figure known as "albertpacino," "alpacino," or "notwonderful." In chats with the Dread Pirate Roberts, the pseudonym Ulbricht used on the site, albertpacino offered information about the law enforcement investigation into Silk Road in exchange for weekly payments. According to the defense team, those chats didn't appear in earlier versions of the forum logs shared by the prosecution and defense, suggesting that someone in law enforcement tampered with evidence to cover up those conversations. The defense team discovered the chats in a newly unearthed copy of the user forums backed up to an obscure subdirectory on the site's server.

The revelation follows the convictions last year of two Silk Road investigators: a Secret Service agent and a Drug Enforcement Administration agent who used pseudonyms to steal bitcoins from the site, attempted to extort money from Ulbricht, and also sold him law enforcement information. As Ulbricht's lawyers continue to appeal their client's conviction on charges including narcotics trafficking and money laundering—as well as the life sentence he received—the defense cites the signs of a third rogue agent with potential access to evidence as an indication that Ulbricht's trial was flawed and unjust.

"We find this to be a significant discovery, considering that we've always believed that there was other corruption that we didn’t know about and the government didn’t know about either," says Lindsay Lewis, one of Ulbricht's attorneys. "It further calls into question the integrity of the entire Silk Road investigation."

For those who have followed the Silk Road saga, the existence of albertpacino isn't exactly a secret. A diary that Ulbricht kept on his laptop, which was introduced as evidence in Ulbricht's 2015 trial, noted that "'alpacino' from DEA has been leaking info to me" and credited the mole with helping him prevent one of the site's drug dealers from being arrested. A text file Ulbricht stored on his computer and labeled as "counter intelligence" also included lengthy messages from alpacino offering his services as a double agent. "There are really tons of useful nuggets that I do have to offer," states one message from alpacino. "And what my birdie doesn't know, he can probably find out."

Until now, alpacino was widely believed to be one of the pseudonyms used by DEA agent Carl Mark Force, who late last year was convicted of money laundering and obstruction of justice and sentenced to six and a half years in prison. Ulbricht's defense team argues that alpacino is, in fact, a different law enforcement official, or at least someone with connections to law enforcement. They point to the fact that the initial court filing that accused Carl Mark Force of corruption listed alpacino as one of his pseudonyms but that the alias was dropped from Force's criminal complaint, indictment and all subsequent court documents. And they note that the $500 a week alpacino demanded from Ulbricht is strangely small compared to the $50,000 lump sum of bitcoins that Force was paid.

Ulbricht's defense says that it's filed a demand that the government turn over any additional information it has about the alpacino figure. It made the filing as part of the pretrial proceedings for a pending set of charges Ulbricht still faces in Maryland.

Even if defense lawyers manage to prove the existence of a third corrupt agent, Ulbricht's appeal of his conviction in the New York trial—the 32-year-old's last chance to escape a life sentence—isn't likely to be affected. A panel of appellate judges reviewing the case is legally barred from considering new evidence not raised at trial or in the appellate arguments Ulbricht's lawyers have filed over the last year. And one of those judges, Gerald Lynch, dismissed arguments about the corrupt agents in an appeal hearing last month. "How is this material exculpatory?" he asked pointedly when the defense described the interference of the two convicted rogue agents in the Silk Road investigation.

The same judge also argued that nothing indicated the two agents had actually tampered with evidence against Ulbricht. Defense attorney Lewis says that indication of evidence tampering may be exactly what the defense has now uncovered. She notes that four different copies of the server's data all either ended before the date when the Dread Pirate Roberts' conversations with albertpacino began in the summer of 2013, or seemed to have the specific conversation deleted. Only the newly discovered backup, apparently made by a Silk Road staffer, includes it. "Someone did not want that to be found," says Ulbricht's lead defense attorney, Joshua Dratel. The defense team hasn’t released the newly uncovered chat logs, and says that rules of evidence in the Maryland case prevent them from doing so.

The clues of tainted evidence are hardly enough to change Ulbricht's legal fate. But Lewis says the defense intends to keep digging. "This is just what we have. It begs the question of what don’t we have," she says. "We don't yet know what we don't know."