At one point, Mr. Pozo dragged Ms. Contreras by her hair as a hotel worker tried to intervene.
Mr. Pozo’s lawyer, Juan Carlos Portugal, denied the death threat and said his client, too, was hurt.
“In our opinion, this is a domestic matter involving infidelity, the details of which I cannot reveal for reasons of gentlemanliness,” he said. “Dragging her doesn’t mean he’s going to kill her, punching her doesn’t mean he’s going to kill her.”
When Mr. Pozo, the son of a City Council member in the Andean city of Ayacucho, where the attack occurred, was arrested, he was recorded on a video telling the police, “Do you know who my father is?”
At trial, a panel of three judges, two of them men, concluded that they “had not observed in the accused hatred or rancor toward women.”
On appeal, two other judges, a man and a woman, also acquitted Mr. Pozo. They cited a diagnosis of borderline personality disorder and said Mr. Pozo was “not capable of raping or attacking other people.”
“If in my case I can’t find justice, I don’t want to even imagine what happens behind closed doors, in a dark room with no witnesses or cameras,” Ms. Contreras said.
Last year, Ms. Contreras was presented with an award by Melania Trump, the first lady, and named one of Time magazine’s 100 Most Influential People. But at home in Ayacucho, she faced harassment. She moved to Lima, the capital, and even now dyes her hair different colors to avoid being recognized.