Letter containing ricin sent to President Obama

The first letter containing the deadly poison was intercepted before reaching the office of Republican senator Roger Wicker on Tuesday.

An FBI official told reporters that both letters were postmarked Memphis, Tennessee.

Following a briefing from law enforcement officers, Senator Claire McCaskill told reporters that police suspected a person who “writes a lot of letters” to politicians, but the police authorities have declined to comment.

In another security alert, two Senate buildings were cleared today because of concerns about suspicious letters and a package. They have since re-opened.

The letter to President Obama was intercepted at a White House mail screening facility, which is not near the White House.

Ricin

An FBI statement said that an envelope addressed to the president and “containing a granular substance that preliminarily tested positive for ricin” had been received.

Secret service spokesman Edwin Donovan said in a statement: “This facility routinely identifies letters or parcels that require secondary screening or scientific testing before delivery.

“The secret service is working closely with the US Capitol police and the FBI in this investigation.”

The discoveries follow the deaths of three people, one of them an eight-year-old boy, in the Boston Marathon bombings on Monday.

White House spokesman Jay Carney said that, according to the FBI, there was no indication of any connecction between the letter and the Boston bombings, which may have been carried out using pressure cookers packed with nails and ball bearings (see FBI picture above).

The investigation into the bombings is focusing on a suspect or suspects believed to have carried heavy bags or backpacks to the finishing line of the marathon.

No arrests

There have not been any arrests and the US authorities say they do not know if the attack was domestic or foreign.

The attack, which also injured 176 people, was the worst in the US since the events of 11 September 2001.

Eight-year-old Martin Richard, from Boston, and Krystle Campbell, 29, of Massachusetts, were killed.

A state-run Chinese newspaper identified the third victim as Lu Lingzi, a graduate student at Boston University.

Among the items recovered at the bomb scene were pieces of black nylon that could be from a backpack, fragments of ball bearings and nails, and possibly the remains of a pressure cooker device.

President Obama, who will travel to Boston on Thursday for a memorial service, has called the bombings an “act of terror”.