“The investigation into the circumstances surrounding the death of Ms. Robinson has been a priority for federal prosecutors and the FBI,” the U.S. Attorney’s Office for the Western District of North Carolina said in a statement Wednesday. “Based on the results of the autopsy and after a careful deliberation and review of the investigative materials by both U.S. Attorneys’ Offices, federal prosecutors informed Ms. Robinson’s family today that the available evidence does not support a federal prosecution.”

Authorities opened the investigation about three weeks after Robinson died, CBS News reported.

The Charlotte, North Carolina, woman, who traveled from the U.S. with a group of six friends, died in late October in Cabo San Lucas. A viral cell phone video showed Robinson being assaulted at the hotel where she was staying.

Some of Robinson’s friends initially told her parents that she died from alcohol poisoning. However, Robinson’s death certificate listed a spinal and neck injury as the cause of her death.

Mexican authorities said in November that they were investigating Robinson’s death as a femicide, meaning she was killed because of her gender. Prosecutors in Baja California Sur said at the time that they were looking to extradite an American woman back to Mexico after Mexican authorities charged her with murder, The Guardian reported at the time.

The U.S., however, has not extradited the person charged in Robinson’s death, WBTV reported.