Big Brother has revealed its saboteur.  And lost her.

Annie Whittington -- who viewers had learned was the twelfth season's secret saboteur only 20 minutes earlier -- was evicted from the Big Brother house during Thursday night's live broadcast of the CBS reality show.

The 27-year-old bartender from Tampa, FL was evicted via a 10-0 vote in which all 10 houseguests that were eligible to vote cast votes for her eviction.

Annie had been placed on the chopping block by Hayden Moss, a 24-year-old college student from Tempe, AZ who had won the season's first Head of Household competition.

Hayden had originally nominated Brendon Villegas and Rachel Reilly for eviction after the pair began a "showmance" relationship that he and his Brigade allies -- Lane Elenburg, a 24-year-old oil rig salesman from Decatur, TX, Matt Hoffman, a 32-year-old web designer from Elgin, IL, and Enzo Palumbo, a 32-year-old insurance adjuster from Bayonne, NJ -- felt might become a threat to their own nascent and still somewhat secret alliance.

However Brendon, a 30-year-old high school swim coach from Riverside, CA, won the subsequent Power of Veto competition and took himself off the block, resulting in Hayden nominating Annie -- who had begun to ally herself with Brendon and Rachel -- for eviction alongside Rachel, a 26-year-old chemistry graduate student and VIP cocktail waitress from Las Vegas, NV.

"I think she's more firmly allied with Brendon and Rachel than she would have been with me," Hayden explained afterwards.

Before Annie's eviction, Big Brother chronicled her "acts of sabotage," which included locking the houseguests out of their storage room pantry for several days, putting tape over photos of fellow houseguests Britney Haynes and Kathy Hillis, and placing electronic beeping devices throughout the house.

"I have been having a blast all week messing with these houseguests," said Annie, who was not eligible to win the season's $500,000 but would have received $50,000 if she had survived five weeks undetected. 

In addition, the houseguests also received a saboteur video in which Annie -- disguised to hide her identity -- falsely boasted that she had "escaped the block this week," causing most of the houseguests to believe Annie and Rachel could not be the saboteur and many to believe it must be Brendon.

"My message helped me in the best way possible," she gushed afterwards.  "It's totally taking the finger off me and pointing it at Brendon, he looks horrible.  This might just save me this week!"

Prior to having the houseguests vote live, Big Brother host Julie Chen gave each eviction nominee a chance to make a final plea and Annie used the opportunity to suggest that Brendon and Rachel were a threat comparable to eleventh-season couple Jeff Schroeder and Jordan Lloyd (who won the season).

"Rachel is a beautiful girl, I'm not going to say anything negative about her except the fact that she has one ingredient I don't have and that's Brendon," she told the houseguests.  "She has Brendon, and Brendon will take her through this game just like Jeff did with Jordan." 

"He's the strongest competitor in this house and you are going to let me lead someone through this game.  And it's my advice to you to please don't think that in another week, or in the second week, you can get him out.  If you have an opportunity now, Rachel is that person.  You're going to give the strongest person in the house more power by keeping his ally."

After she was evicted, Annie blamed her quick eviction on her saboteur status.

"I really do believe the reason I'm here is because I tried to play twice the game in half the time.  If 'Annie' had just gone in the house I wouldn't have played as strong as I did, so I think I played a little too hard and put a target on my back," she told Julie.

In addition, she also reiterated her belief that Brendon is the game's strongest competitor.

"To be able to convince all of them that [Rachel] should stay is genius.  I don't know how he did it and I can't wait to watch," Annie said.  "He's got a fire in him and he will go far in this game."

Following Annie's interview, the 12 remaining houseguests -- minus Hayden, who as the outgoing HoH, was ineligible to compete -- competed in the season's second HoH competition.

Dubbed "Majority Rules," the challenge required the houseguests to guess which of two houseguests the majority of the house had given as the answer to a series of questions.  A wrong guess would eliminate a houseguest from the challenge while the rest would advance to the next round, with the last remaining houseguest becoming the second Head of Household.

The challenge ended with three houseguests -- Rachel; Britney, a 22-year-old hotel sales manager from Huntington, AR, and Monet Stunson, a 24-year-old model from Glen Carbon, IL -- still in the running, resulting in a tiebreaker question.

Rachel won the tiebreaker, becoming the season's second HoH.

Annie's saboteur status will be revealed to the houseguests during Sunday night's Big Brother broadcast,  according to Julie.  However, CBS has revealed all of this season's Big Brother houseguests are being sequestered following their evictions (only jury members are typically sequestered) -- prompting speculation that Annie or another pre-jury houseguest may receive a second chance to return to the house.