In 2014, Cheng Le asked a Federal Bureau of Investigation analyst posing as a vendor on a website called Evolution to sell him ricin in the form of "simple and easy death pills" that he could resell, prosecutor Andrew Beaty told jurors in Manhattan federal court on Monday.
Beaty said a search of the 22-year-old's apartment found the fake ricin the FBI had shipped to him along with castor bean seeds, which are used to make ricin and Le's computer, which was still logged onto the website.
"Although the defendant may have thought he was protected by the anonymity of the 'Dark Net,' the evidence will show the defendant was caught red-handed," Beaty said.
Law enforcement has been cracking down on illegal activity involving online black markets operating on a hidden network of websites that can only be accessed using specialised browsers.
Those websites had included Evolution, which became the largest marketplace following the FBI's 2013 seizure of Silk Road, where drugs and other items could be bought with the digital currency bitcoin. Evolution abruptly shut down in March this year.
Patrick Brackley, Le's lawyer, said prosecutors had no proof that Le was the computer user who sought the ricin. He urged jurors to scrutinise the evidence and not convict Le based on "the fear of things."
Le has been charged with attempting to acquire a biological toxin for use as a weapon and two other charges. He faces life in prison if convicted.
Prosecutors said that December 2014, Le sought out an Evolution vendor called "Dark_Mart" known for offering ricin.
Mark Walker, the undercover FBI intelligence analyst, testified the FBI had taken control of that vendor's account.
Beaty said in his opening statement that Le, who went by "WhenInDoubt," discussed in encrypted messages his plans to sell the ricin to customers for their own use.
Prosecutors said Le wanted the ricin made into a pill that would be mixed with ordinary vitamins, saying "as the target takes the medicine every day, sooner or later he would ingest that poisonous pill and die."
According to prosecutors, Le wrote, "After all, it is death itself we're selling here, and the more risk-free, the more efficient we can make it, the better."
