The concept you are asking about is called ‘lashon hara’ [covering the areas of gossip, slander, and tale-bearing]. Literally It translates as the evil tongue, or more colloquially, evil speech. There are numerous and extensive discussions of this topic. One of the foremost Jewish authors in this area is called the Chofetz Chaim (Desirer or Seeker of Life) after the title of his book on this topic, taken from Psalm 34:12-15. The actual name of the author was Rabbi Israel Meir Kagan.
Because gossip and slander are understood to be irreparable (often demonstrated by a story: a woman who gossips is told by her rabbi to take a feather pillow to the top of a high hill on a windy day, and cut it open. The wind takes all the feathers and scatters them everywhere. The rabbi then tells the woman to gather the feathers, to which she says it is impossible, and the rabbi tells her that this same impossibility also applies to words that are sent out in the world), they are something for which it is very difficult to achieve Teshuvah (repentance and repair). The reputation and feelings of the person about whom one has gossiped are injured/damaged, and they cannot be made whole again.
The rabbis also teach that lashon hara destroys three persons: the one who says it, the one who hears it, and the one about whom it is said. In a particular form of lashon hara, the rabbis felt it was even more severe. This is the basis for your question. This was the instance in which the gossip may be true, but the spreading of it completely destroys the person. They term this as ‘halvanat panim’, the whitening of the face. In a slightly hyperbolic language, they say that this is tantamount to murder, as one removes the blood from the person (their face is drained of color and blood), and destroys them. A discussion of this phenomenon is explained (in BT Seder Kedoshim Tractate Arachin folio 5b) starting with the teachings of the school of Rabbi Ishmael. In this way, gossip is equated to murder (shedding of blood).
Rabbi Joe Blair
Answered by: Rabbi Joseph Blair