The White House this week was sent a letter that tested positive for cyanide, U.S. media reported Tuesday

The White House this week was sent a letter that tested positive for cyanide, U.S. media reported Tuesday, in yet another piece of bad news for the Secret Service.

"On Monday 3/16/15, an envelope was received at the White House Mail Screening Facility. Initial Biological testing was negative; however, on 03/17/15, the chemical testing returned a presumptive positive for cyanide," Secret Service spokesman Brian Leary said in a statement on CNN. "The sample was transported to another facility to confirm the results."

Because an investigation is under way, the Secret Service had no additional comment, Leary was quoted as saying.

There were no injuries or exposure concerns for the person at the mail-sorting facility who opened the letter, an unidentified law enforcement official told CNN.

It was just the latest incident to hit the Secret Service, which has been rocked by scandals.