Letter to White House Tests Positive for Cyanide

A letter addressed to the White House is undergoing a third round of testing for cyanide.

The Secret Service says initial tests were negative. But a second round conducted Tuesday returned a "presumptive positive" result for cyanide.

The letter was received Monday at a government screening facility located away from the White House and its surrounding buildings.

"As this is an ongoing investigation, the Secret Service will have no additional comment," the agency said in a statement.