But they said they contacted federal prosecutors and Mexican diplomats to try to extradite the woman to face charges in Mexico.
Robinson’s death at a resort in the Baja resort town of San Jose del Cabo shocked people in both countries. The video raised suspicions that Robinson may have died at the hands of people she was traveling with.
Local prosecutor Antonio López Rodríguez said the case was being treated as a potential homicide and a warrant had been issued for the suspect. However, the group Robinson was traveling with left Mexico after being found dead in a rented villa.
District Attorney Daniel de la Rosa Anaya said the suspect was also an American, but did not identify her.
Local media in Charlotte, North Carolina reported that people Robinson was traveling with gave different versions of how she died, but an autopsy revealed she died of a serious injury to the spinal cord or neck.
Video apparently recorded at the luxury villa in San Jose del Cabo shows a woman, apparently an American, beating up another woman identified as Robinson.
The video has been reposted several times on social media. In it, a man with an American accent is heard saying “Can you at least fight back?” The man did not appear to intervene in the beating.
The video raised questions about why no one intervened in the alleged beating, or why the people she was traveling with allegedly beat her.