A letter sent to the White House on Monday actually contained saliva, after a test suggested that it might have contained cyanide, according to ABC News.
The White House said on Monday that it was sent a letter that contained a suspicious substance. The substance was tested and came back negative for toxins but a second round of tests suggested that the liquid could have been cyanide, spurring yet another round of testing.
The third round concluded that the substance contained a few trace amounts of cyanide, according to ABC News, but was mostly saliva.
ABC News said that the person who sent the letter is believed to be a homeless man in or around Chicago who smokes often which would produce the small amounts of cyanide.
If the first test was negative (correctly, it turns out), why was there a second test?
Is it SOP to just keep testing something until a false positive can be had?
There is probably a less sensitive screen and then a more sensitive test. Good forensic testing usually relies on two tests, sometimes from two reference labs.
The breath of the person who sent this is probably as toxic as cyanide.
The guy could have also been chewing apple seeds or been sucking on cherry, apricot or peach pits too prior to sending off that letter. All contain small amounts of cyanide. Its good to know that the WH has such a high level of security when it comes to detecting teeny-tiny amounts of poisons though.
Saliva chock full of DNA…excellent!