Selena's death threats from Bieber fans

Since Justin Bieber and Selena Gomez have been seen together out a lot, also seen on a yacht hugging and kissing it's indicated that their dating. Now Bieber fans are tweeting Selena death threats. Saying "I'm gonna kill you", "your a b****", and many more. I personally think that it's non of their business. It's Justin's business on who he dates, and same to Selena.