Heckler stressed that the toxin was "very potent" and that Helman "hit the jackpot."
"He made ricin," Heckler said, "and if you lick that card, you're dead."
Helman had bragged of the toxic card to a coworker at Target in Warrington on March 6, according to a probable cause affidavit. The coworker then notified police, the affidavit says, and police called the man's home and spoke to his mother, asking whether she had retrieved the mail that day.
The mother, who, like her son, was not identified, told police that her daughter was outside retrieving the mail at that moment, according to the affidavit. Police advised them to return the mail to the mailbox, and authorities then came to the home to retrieve the card.
Initial tests did not indicate that the card contained ricin, according to Heckler.
When Helman was first questioned about the incident, on March 7, he told police that he had only coated the card with sodium hydroxide, the affidavit says, which he chose because it resembled the toxin anthrax.
Helman also admitted to sending threatening messages to the man via Facebook, according to the affidavit, and police seized from him what appeared to be sodium hydroxide and a notebook with a ricin recipe after questioning.
Helman was charged March 7 with terroristic threats and harassment.
In the meantime, Heckler said, authorities sent the card away for subsequent lab tests. The results, returned to the District Attorney's Office on Tuesday, confirmed that the card had traces of ricin, according to Heckler.
The dose on the card was not in a powder form that could spread, Heckler said, and there were no indications that anyone had been harmed by it.
But Heckler added, "If properly deployed, the stuff he put in that envelope would have killed a whole bunch of people."
The Warminster Police Department subsequently led numerous agencies in arresting Helman on Wednesday night at his Hatboro apartment, Heckler said. Other agencies included Hatboro police, SWAT and Hazmat teams, and the FBI.
Heckler said those teams were deployed in case Helman had more ricin, a poison that, according to the CDC, is found naturally in castor beans. It can be made by heating the waste material that results from processing the beans, the agency says, and ingestion can lead to death. There is no antidote, the CDC says.
Helman could not be reached for comment.
He was arraigned about 8 p.m. in front of Judge Charles W. Baum, according to Assistant District Attorney Antonetta Stancu, and was being held in Bucks County Prison without bail.