Answer: she tells the truth.
The author explains that she had to participate as a witness in a trail against her friend Paco, who killed a man to save her life.
Everyone expected her to protect Paco since he was part of her group, he was "blood." However, when she sees the mother of the boy accused of Paco's crime, she remembers her father, who was wrongly send to jail.
At the though repeating his father's situation, the author changes her mind and decides to tell the truth.