(CNN) -- The information age has made it easier to find instructions for anything -- even how to extract the deadly poison ricin from castor beans.
At least 10 ricin-laced or suspected ricin-laced letters have been sent to government officials in recent weeks, including President Barack Obama.
Should the public be alarmed?
Not necessarily, analysts say. Just because castor beans and instructions of how to extract ricin are readily available doesn't mean this toxin is easy to produce or effective, they say.
"The recipe for it is easily accessible on the Internet," CNN national security analyst Fran Townsend said Thursday on "Piers Morgan Live." "The basic recipe is not so hard; what's difficult is weaponizing it."
Even if a pinpoint of ricin is ingested, it can be fatal within days. And there is no cure. But mailing some poison in an envelope makes for a crude weapon, Townsend said.
Former New York City Police Commissioner Bill Bratton put it more bluntly: "Ricin is probably one of the worst ways to try and kill somebody."
He added, "It's intended, I think, to attract publicity -- which it certainly is -- and to potentially intimidate."
This week, authorities were interviewing a man in New Boston, Texas, in connection with ricin-tainted letters sent to Obama and New York Mayor Michael Bloomberg, a person with knowledge of the investigation told CNN.
Also, the FBI announced Thursday its agents are looking for a letter sent to the CIA that they believe is similar to other letters, mailed from Spokane, Washington, that contained ricin.
In April, letters were sent to Obama; Sen. Roger Wicker, R-Mississippi; and Sadie Holland, a judge in Lee County, Mississippi. James Everett Dutschke of Tupelo, Mississippi, has been charged with possession and use of a biological agent in connection with that case.
Before this recent spate of suspected ricin letters, eight people had been arrested in the United States since 9/11 for attempting to make the poison with the intent of using it for an act of politically motivated violence, according to terrorism data collected by the New America Foundation. But only two of those individuals succeeded in producing the ricin.
In short, ricin is a poor choice for someone trying to inflict mass casualties because it must be directly injected or ingested in some way by the victim, CNN national security analyst Peter Bergen wrote recently.
Only one person, a Bulgarian dissident who died in 1978, appears to have been a victim of a successful ricin attack in more than three decades, according to Bergen.
It remains unclear what the motivation is behind the recent letters.
The letter sent to Bloomberg -- and an additional one sent to a gun control group he founded -- contained what could be described as an overzealous pro-gun position.
"You will have to kill me and my family before you get my guns," the letters said, a law enforcement official told CNN. "Anyone wants to come to my house will be shot in the face. The right to bear arms is my constitutional God-given right and I will exercise that right 'til the day I die. What's in this letter is nothing compared to what I've got planned for you," the note inside each envelope said, according to the official.
CNN obtained a copy of the letter sent to mayors' gun control group, postmarked May 20 in Shreveport, Louisiana, and the wording matched the account provided by the law enforcement official.
The letter addressed to Obama that was intercepted Wednesday appeared similar to these letters.
The suspected ricin letters in Washington state appear to be a separate incident.
These letters were sent to a federal judge, a Spokane post office, Obama and the Fairchild Air Force Base, the FBI said. The FBI confirmed Friday the presence of ricin on the letter sent to the Air Force base near Spokane, the agency said.
There are similarities between these letters and one that authorities are looking for that was sent to the CIA, officials said.
Matthew Ryan Buquet, 37, was arrested last week in connection with the letter sent to the judge, which contained a message threatening to kill him.
CNN's Greg Botelho, Jim Acosta, Carol Cratty, Dana Bash, Ted Barrett and Alex Mooney contributed to this report.