http://en.wikipedia.org/wiki/Sigil_of_Baphomet
I think this is maybe what you are referring to.
Satanism uses the pentagram but upside down with two points facing upwards and it is also not called a pentagram but the Sigil of Baphomet.
It also depends on what religions bible you refer to. In the wiccan bible it is taken to represent the power of the elements and nothing to do with evil at all.
The pentagram was the official seal of the city of Jerusalem for a time. Most Christians, probably due to their misinterpretation of symbols used by ceremonial magicians, came to associate it with Satanism and subsequently rejected the symbol sometime in the twentieth century
Once the symbols had appeared in the banned books of sorcery, they became connected with 'the occult'. The writer who really nailed that together was named Eliphas Levi (Alfonse Louis Constant, a failed roman cleric, later socialist and occultist). He sort of reinvented occultism in the middle 19th century, and he made a big deal of the pentagram, and more or less invented the 'inverted pentagram' as a symbol of satanism.