Sainsbury could become the target of a share raid that could lead to an attempt to take over of the supermarket giant, a report by the Telegraph said over the weekend.According to the newspaper, activist hedge fund Crystal Amber Fund is believed to be holding discussions with a number of international investors, including an unnamed US investor who is looking to purchase a stake in the company.Crystal Amber is reportedly currently now planning to build a stake in the FTSE 100 group worth "tens of millions of pounds".The news prompted its shares to rise around 1.2% in the first hour of trading on Monday after spiking at the opening bell.