A Manhattan man has been charged with trying to acquire the deadly poison ricin after he allegedly asked an FBI undercover employee online to deliver "simple and easy death pills" to his postal box and picked up a package containing a fake pill.

The Dec. 23 arrest of Cheng Le, 21, was announced Tuesday after court papers were unsealed in Manhattan federal court. Le has remained incarcerated on charges of attempting to acquire and distribute ricin and committing postal fraud.

He is to appear in court Friday, and his lawyer, Patrick J. Brackley, said: "Mr. Cheng will be pleading not guilty at his arraignment in Friday. It's a complex case and we are still establishing the facts."

U.S. Attorney Preet Bharara said Le tried to acquire ricin over the dark web, an Internet marketplace where those peddling illicit goods, including drugs, weapons and biological toxins such as ricin, can more easily hide their identities.

"Thankfully, with the help of our law enforcement partners he was intercepted," Bharara said.

In a criminal complaint, the FBI said an undercover employee last summer assumed an identity on the dark web that previously had been used by a trafficker in illicit materials. The FBI said the employee struck up a conversation online in early December with a ricin buyer who was seeking three to five lethal doses of ricin to send to a client and suggested it might make a regular business since he had "buyers lining up."

"If you can make them into simple and easy death pills, they'd become bestsellers," the buyer said, according to the complaint.

The buyer said he planned to mix the toxic pill in a container of pills so that "sooner or later he'd ingest that poisonous pill and die."

"Even if there is a murder investigation, they won't find any more toxin. 100% Risk Free," the buyer wrote, according to the complaint. "I'll be trying out new methods in the future. After all, it is death itself we're selling here, and the more risk-free, the more efficient we can make it, the better."

In a Dec. 21 conversation, the buyer told the undercover FBI employee that the shipment should occur so that other black market users could not see the order, the complaint said.

Authorities said Le was arrested after he picked up a sham shipment of a supposedly poison pill inside a bottle of other pills from a shipping store's postal box near his home. He was wearing latex gloves at the time, they said.

If convicted, Le could face up to life in prison because the purpose of purchasing the toxin was to use it as a weapon, authorities said.

"In his desire to acquire this potentially deadly toxin, he picked his own poison and now faces the consequences of the justice system," George Venizelos, head of the FBI's New York office, said.