In this passage, Angela Vicario tells her brothers that Santiago Nasar was the person who violated her before her wedding. The passage presents the revelation of Nasar's name almost as if it causes Angela's resurrection from the dead. 

At the beginning of the passage, Angela is badly beaten, and she is lying on the couch. She later says that "the drowsiness of death had finally been lifted from me," an image that creates the idea that she has reached or almost reached the point of death and is then reborn when she gives her brothers Nasar's name. 

To find the name, she "looked for it in the shadows," conveying the image of her searching the darkness of her own soul to find a name that will satisfy her incensed brothers. Using metaphorical language, Angela's production of Nasar's name is compared to a "well-aimed dart," conveying the idea that she knows that Nasar's name will satisfy her brothers and also inflict damage on Nasar. However, she is also a victim, like Nasar, as she knows that she has no free will to tell her brothers the truth. She is compared to "a butterfly with no will whose sentence has always been written." In other words, she has little control over her own fate and tells her brother a lie to protect her own fragile life.

This passage is organized so that Angela's metaphorical resurrection occurs when she reveals the name of her violator. The beginning of the passage contains the fury of the brothers, and then it moves on to Angela's emergence from near-death to life with the lie that sacrifices Nasar. 

This passage from Chronicle of a Death Foretold has the feel of a nasty police interrogation--the kind that isn't supposed to exist. 

Angela is bruised and can think of nothing but sleep, but isn't allowed to sleep.  The chief investigator, the forceful one, arrives and picks her up by the waist and sets her on the table.  Trembling with rage, he orders her to confess.  The accused says whatever will end the interrogation and allow her to get some sleep. 

And in fact the results of this interrogation are accepted much as the results of a police investigation--as accurate and binding.  No further attempt at gathering evidence is performed.  Angela's words end the investigation, and begin the sentencing and execution.

The narrator interprets what he knows of her confession and relates that interpretation by using a metaphor.  She looks for one name that will work among many and speaks the first name she thinks of.  By doing so, she pins Nasur to the wall like a collected butterfly.

The metaphor presents the image of a butterfly pinned to the wall, wings spread, and suggests, then, Nasur pinned to the wall with darts, arms spread--in the posture of the crucified Christ.  Thus, the metaphor creates images that then create a biblical allusion: that of the crucified savior, or in this case, the crucified scapegoat.  As Christ suffered for the sins of humanity, Nasur will suffer for the sins of Angela.