London: Writer Ian Halperin says his book will reveal more shocking details of pop star Britney Spears' personal life and her friends' circle.

Contactmusic.com reports Halperin spent 18 months conducting an undercover investigation by getting close to Spears and her close friends and he will now release a book based on his findings. He revealed that Spears attempted suicide twice and now says that her problems were caused by drugs and her friends' circle.

He said: "I saw a lot. I partied with her and was able to really monitor what type of stuff she was using. It's very concerning. But the book is mainly about her handlers, how sleazy and destructive they are towards her. The people around her are like vultures."

Halperin vows the book will not hurt Spears and says she is basically a good person adding: "She is actually a very caring mom."

But he is also concerned that she is suffering a "catastrophic relapse" of her bipolar issues.

"Spears herself warned me that with her, it's always two steps forward, one step back."