Homicide detectives said Mayra Lissette Contreras, 22, of Pacoima died just one day after the two sisters injected her with silicone.
"She went to that house for cosmetic purposes on the morning of July 23," said Los Angeles police Deputy Chief Kirk Albanese. "On the evening of July 24 she was pronounced dead at a local hospital."
About three weeks before Contreras's death, the sisters were arrested and charged for practicing medicine without a license. They posted bail and it was around that time that Contreras received her last set of injections.
"We believe they're on the run or possibly out of the country by now," said Det. Gene Parschall.
Though authorities said the sisters have not been charged in connection with Contreras's death, they are the prime suspects in the investigation.
"She was a wonderful person," said Gerardo Olvera about his 22-year-old wife and mother of his two children. "She was a good mother, a good wife.
"I'm here to ask the public to help me and my family to bring these people to justice," Olvera said at a press conference. "She was very young and my kids are only 2 and 3 years old and they really need her."
According to investigators, the Viveros advertised by handing out business cards in parking lots, leaving them on car windshields.
Anyone with information of the whereabouts of the Viveros sisters is asked to call authorities at (800) 222-8477.