The body of a beloved teen football player who died during a Fourth of July boating trip with friends is being flown 800 miles for an independent autopsy after his family retained a famous civil rights attorney. 

Nolan Xavier Wells, 18, was found dead on the northwestern tip of Horn Island, just south of Ocean Springs, Mississippi, on Monday.

He stayed behind on the island while his friends returned to the mainland on a boat, according to authorities. His body was found after his mother filed a missing person report on Sunday night.

Jackson County Sheriff John Ledbetter said authorities do not suspect foul play and believe that Wells had chosen to stay on the island. Authorities initially believed that he died from drowning, although no cause of death has officially been released.

However, attorney Ben Crump, who has been involved in multiple high-profile civil rights cases, including representing George Floyd's family, has raised questions surrounding the teen's death. 

The family's legal team has demanded a thorough and urgent investigation and has asked his body to be flown to Washington DC for an autopsy.  

Crump told ABC News that the teen's body was being flown to DC on Thursday afternoon. 

The attorney explained that Wells' friends had his phone when they left him on the island, which he alleged included a video of the teen and another individual 'yelling at one another on the boat.' 

Crump claimed that when the family got Wells' phone back, messages had been deleted. 

'He was a good kid, he was beloved, he was a college athlete, he had everything going for him — so to go on that island for Fourth of July weekend and not come back is what is concerning everybody, especially when we hear the contradictions,' Crump said.

Crump also mentioned the deleted messages and video altercation in an interview with Don Lemon, which he referred to as 'inconsistencies' in the investigation. 

The civil rights attorney has also said that the Wells family told him the teen could swim, and that they were not 'just accepting that Nolan drowned accidentally.' 

The National Action Network, a civil rights organization led by Reverend Al Sharpton, has also called for a full and transparent investigation. 

'A young man left his home to celebrate the Fourth of July with friends, and he never came back. His mother deserves answers, and his family deserves the truth,' Sharpton said in a press release. 

'We are not here to jump ahead of the facts. We are here to demand that the facts come to light, fully, honestly, and without delay. That means a complete and transparent investigation. That means releasing every record.' 

The National Action Network added that the organization stands with Wells' family as part of its mission to ensure the deaths of young black men are properly investigated, and grieving families are told the truth. 

Crump and Sharpton are expected to discuss Wells' death at a press conference on Friday afternoon at NAN's headquarters in Harlem. 

The Daily Mail has reached out to the sheriff's office for comment on Crump's claims.  

It is unclear exactly why Wells had stayed back on the island. Ashlee Cole, a Mississippi judge and mother of one of the teen's friends on the trip, said in a social media post that he decided to stay back after their boat suffered a mechanical problem. 

'Nolan made a decision to stay on the island and return inland later with another group of friends,' she said.

'I have the utmost respect for her and all of the Wells family. We mourn the loss of Nolan with them,' Cole said of Nolan's mother. 'Our son, Warren, loved Nolan dearly.

'My family is hopeful that this information will help to redirect the attention to the Wells family, their grief, and their need for our community’s support.'

Wells was a budding college football player for Southwest Mississippi Community College. He had previously played for Ocean Springs High School's team.

Jake Bramlett, Ocean Springs' head football coach, said in a statement to WLOX: 'We are devastated by Nolan’s passing. He was the kind of son, teammate, friend and student that every coach hopes to have in a program.

'Nolan was so much more than an outstanding football player. He carried himself with humility, treated others with respect, worked hard and led by example.' 

Wells' mother, Christine Wonsley, broke the news of her son's death in a Facebook post, writing, 'My heart is broken for our sweet son who was always willing to cheer and uplift others. Nolan was a special soul, God took his time creating our son.'  

A GoFundMe was launched for the teen's family for funeral expenses and additional support. 

The Daily Mail has reached out to Ben Crump's office for comment and an update on the independent autopsy.