Senator letter 'did contain ricin'

The presence of ricin in a letter sent to US Republican Senator Roger Wicker has been confirmed by a laboratory, an official has said.

The US Senate sergeant-at-arms Terrance Gainer said the lab tests confirm field testing that indicated the presence of the toxin.

He said that the ricin, which was found on Tuesday at a Maryland mail processing centre, was not weaponised.

Yesterday, the FBI arrested a Mississippi man suspected of sending the letter to Mr Wicker and another to President Barack Obama. Kevin Curtis is expected in federal court later today.

The FBI has not yet reported the results of its testing of the material.

The arrested man reportedly believed he had uncovered a conspiracy to sell human body parts on the black market, and claimed “various parties within the government” were trying to ruin his reputation.

Curtis, 45, was arrested at his home in Corinth, Mississippi.

Both letters said: “To see a wrong and not expose it, is to become a silent partner to its continuance.”

They were signed: “I am KC and I approve this message.”

The letters were intercepted before reaching the White House or Senate, but the scare set the US capital on edge a day after the Boston Marathon bombings.