An ethnic Russian teenager has been accused of dismembering her acrobat mother and younger sister and storing their body parts in plastic bags, Mexican officials said.
Anastasia Lechtchenko, 19, was arrested in the violence-plagued town of Tijuana, where the grisly murders took place on June 11.
"According to our investigation, Anastasia Lechtchenko acted alone, no third parties as participants in the crimes," Baja California state deputy prosecutor Jose Maria Gonzalez said.
She was arrested "with the help of tips from people and social media" in a park about five blocks from where the hacked body parts of her mother and sister were discovered, Gonzalez said.
Authorities said Lechtchenko confessed to killing her mother Yuliya Masney Safonchik, 45, and her 12-year-old sister, Valeria Lechtchenko.
The dismembered corpses were discovered in plastic bags and police said Valeria's eyes had been gouged out.
The blonde 19-year-old appeared calm and emotionless in court Friday wearing a blouse and jeans and did not speak.
Police said earlier that Lechtchenko, perhaps under the influence of drugs, was the prime suspect but did not have enough evidence to detain her.
Her parents, both of Russian origin, were acrobats, and worked with the Atayde circus in Mexico.
They had lived in Tijuana, near the US border, for 13 years, though the father is believed to have left the family three years ago.
Both daughters were born in the northern Mexican state of San Luis Potosi.