An autopsy has found no concrete cause of death for Nolan Wells, the black American teen who was found dead on a Mississippi island he travelled to with his friends on July 4th.

Civil rights attorney Benjamin Crump, speaking on behalf of the family, told United States (US) media on Wednesday that an autopsy carried out on Wells’ body was inconclusive, providing little new information in the case that has gripped the country in recent weeks.

Wells’ mother, Christine Wells, spoke during the conference as well, pleading for answers from law enforcement whom she indicated the family has not heard from despite preliminary autopsy results.

She expressed fears that lawmen had prematurely concluded her son’s death was an accident.

Eighteen-year-old Wells reportedly left the Mississippi mainland with a group of friends for a boating trip on a nearby island to celebrate the 4th of July but did not return home with the group.

After receiving a call from one of the young man’s friends, his parents reported him missing around 11:00 pm that day and immediately began to search for him.

By July 5th, police and marine assets had joined the search while his cell phone was tracked to a house on the mainland.

Police reports cite eyewitnesses who claim Nolan had decided he would stay behind and travel back with another group, an account his family and friends told the media is out of character.

Two days later, Wells’ body was found near the island’s shore on July 6 with no obvious injuries.

The case has gained the interest of the American public, fuelled by Mississippi’s history of racism, and speculations that Wells was the only African-American in the group on the island trip.

No official cause of death has been shared by Mississippi lawmen, and an official state autopsy is still pending while several of the young people in Nolan’s group have retained attorneys.