Letter sent to White House tests tentatively for cyanide

An envelope addressed to the White House has tentatively tested positive for cyanide, the Secret Service said Tuesday night.

The letter was received at an off-site mail screening facility Monday. Initial biological testing was negative.

The agency said additional testing Tuesday returned a "presumptive positive" for cyanide.

The sample has been taken to another facility for further testing.

The Intercept website, which first reported the incident, said the envelope contained a milky substance and was in a container wrapped in a plastic bag. The site said the envelope bore the return address of a man who has sent multiple packages to the executive mansion since 1995, including one that was covered in urine and feces and another that contained miniature bottles of alcohol.

The Secret Service, which is responsible for the safety and security of President Barack Obama and his immediate family, said its investigation into the letter was continuing and it will have no additional comment on the matter.

There were no injuries from the envelope, according to media reports.

Suspicious letters often are sent to some of the country's leading politicians, including the president. Some test positive for hazardous substances while others include threats of death or other physical harm.

In June 2013, a West Virginia man was indicted on charges of threatening to kill Obama and his family in a letter that included profanity and racial slurs. A federal judge later dismissed the charges after forensic handwriting analysis conducted by the Secret Service showed that 20-year-old Ryan Kirker, of McMechen, West Virginia, didn't write the letter.

Two months earlier, letters sent to Obama, Sen. Roger Wicker, R-Miss., and Mississippi judge Sadie Holland tested positive for the poison ricin. The letters addressed to the president and to the senator were intercepted before delivery, but one letter reached Holland. She was unharmed.

James Everett Dutschke of Tupelo, Mississippi, pleaded guilty in January 2014 to sending the letters and was sentenced to 25 years in prison.

The most recent letter arrived after a series of Secret Service lapses. 

Earlier this month, the Department of Homeland Security announced it was investigating two senior Secret Service agents accused of crashing a car into a White House security barrier.

In the last six months, several top agency officials, including former Director Julian Pierson, have been forced out amid revelations of multiple, serious presidential security breaches. In September, a Texas man armed with a knife was able to climb a White House fence and run deep into the executive mansion before being apprehended.

An internal investigation and an outside panel report both described serious problems within the agency.

A four-member panel of former senior government officials concluded in a report released last year that the agency was too insular and starving for leadership.

The panel recommended an agency outsider to replace Pierson, but Obama earlier this year tapped Joseph Clancy,a retired agent who led the agency on an interim basis after Pierson's ouster.

Al Jazeera and wire services