Kobe Bryant and his daughter Gianna's cause of death has been revealed, almost four months after the helicopter crash.

The Los Angeles County Department of Medical Examiner-Coroner says the basketball star and his 13-year-old daughter died from ''blunt trauma'' in the crash, which happened in January 26 in Calabasas, California.

According to TMZ, the pilot Ara Zobayan was tested for drugs and alcohol at the time but the report revealed that ''toxicological testing did not detect the presence of alcohol or drugs of abuse''.

It added: ''Substances tested for include: benzodiazepines, cocaine, fentanyl, heroin, marijuana, opioids, phencyclidine, and amphetamines.''

It comes after Vanessa filed a wrongful death lawsuit following the passing of her husband and daughter, who were among nine people to lose their lives when the private helicopter crashed.

According to documents, Vanessa claims the helicopter should never have been placed in the situation it was in before the incident on January 26, as Island Express allegedly broke several flight rules.

The lawsuit alleges the company was only allowed to fly under visual flight rules, and the conditions on the day of the crash were not conducive for such flying, as there was low fog. Documents also claim the pilot was travelling at 180 miles per hour in the fog in a steep decline, and alleges he made a number of other errors in judgement on the day.

Vanessa is alleging Ara Zobayan - who also lost his life in the crash - failed to properly monitor and assess the weather prior to takeoff, failed to obtain proper weather data prior to the flight, failed to abort the flight when he knew of the cloudy condition, failed to maintain control of the helicopter, and failed to avoid ''natural obstacles'' in the flight path.