The FBI has announced that a letter addressed to the White House has been quarantined after testing positive for the poison ricin. The agency said Wednesday evening that it had a suspect in custody.

Federal agents have arrested a man they believe mailed the letters to President Obama and Senator Roger Wicker that “preliminarily tested positive” for the poison ricin.

The FBI named a Paul Kevin Curtis of Corinth, Mississippi as its arrest.

Although the letter initially tested positive for the deadly poison, official test results will be available in 24 to 48 hours. According to a law enforcement official, preliminary tests are "unreliable" and often result in false positives.

Extracted from a castor oil plant, ricin is a highly toxic substance, even a dose as small as few salt grains – injected or inhaled – can kill adults.

First symptoms appear as early as 4-8 hours and as late as 24 hours after exposure, with death typically occurring within 3-5 days of the initial exposure. Ricin is harmful to the whole body, proving deadly by penetrating cells and preventing them from creating the proteins they need.

The toxin can be in the form of a powder, a mist, or pellets or it can be dissolved in water or weak acid.

In an intelligence bulletin obtained by AP, the FBI says that both letters say: "To see a wrong and not expose it, is to become a silent partner to its continuance." Both are signed, "I am KC and I approve this message."



Federal officials said at that time that they believed they knew who sent the letters.

Information regarding the suspect, Paul Kevin Curtis, has since emerged via online profiles and YouTube. Evidently, 45-year-old Curtis is a father of four, an Elvis impersonator, a self-proclaimed member of Mensa and a martial artist.

According to Prentiss County Sheriff, Curtis, who suffers from severe psychological issues, has been arrested four times before, once for stalking. His LinkedIn profile currently has a long list of seemingly unrelated professions, spanning everything from “reflexology massage therapist” to “Guiness World Record recipient” and “published song writer.”

According to his Twitter feed, Curtis attempted to contact Huffington Post reporter Radley Balko in December of 2011 with claims that he was being targeted due to alleged whistleblowing activities.

@radleybalko please help me..I am in fear for my life after blowing whistle at largest rural healthcare org in the U.S. (Mississippi) — Kevin Curtis Live (@kevincurtislive) December 20, 2011

Meanwhile, "A letter addressed to the president was received at a remote screening facility containing a suspicious substance. We are working closely with Capitol Police and the FBI in this investigation," a Secret Service spokesman said in a statement.

The letter, which was received at an off-site location away from the White House on Tuesday, is currently under investigation after being intercepted at a postal screening center.



"This facility routinely identifies letters or parcels that require secondary screening or scientific testing before delivery," White House spokesman Edwin Donovan said in a statement.

It arrived the same day as an envelope addressed to US Senator Roger Wicker, which tested positive for ricin. The envelope was postmarked Memphis, Tennessee and did not have a return address. The newest letter is believed to be from the same sender..

Arizona Senator Jeff Flake also received two suspicious letters at his Phoenix office on Wednesday. He later confirmed that no dangerous materials were found inside the envelopes.



Michigan Senator Carl Levin and Alabama Senator Richard Shelby reportedly received suspicious letters, as well.

