The FBI and LAPD have been called in after Dancing With The Stars contestant Bristol Palin - the daughter of Sarah - received a 'suspicious package' at the CBS studio lot in West Hollywood last week. Law enforcement sources tell that both federal agencies are taking the threat 'very seriously."

A package containing a white powdery substance addressed to Bristol was opened at the studio, though it was the foreboding letter attached that has caused the most consternation amongst cast and crew. The note demanded that show producers remove Palin from the current series of the reality dancing show, or else. Initial tests revealed the white powder was not harmful, though investigators are understandably keen to trace the sender, especially considering this isn't the first that the Bristol has received this type of threat. Back in 2010, CBS received a suspicious letter containing a similar demand to remove the polarizing 21-year-old from their broadcasts.

The 15th season of Dancing with the Stars - dubbed the 'All Star' competition - brings together the most popular contestants from the franchise thus far. Palin is competing against the likes of Kirstie Alley, Emmitt Smith, Drew Lachey and Kelly Monaco.

Considering she finished third during her first stint on the show, it's highly unlikely that she'll triumph this time around.