Nolan Wells' Family Calls for Federal Investigation, Watch Live Stream

Nolan Wells' family is turning up the pressure on authorities ... calling once again for the FBI and DOJ to step in and investigate the 18-year-old's mysterious death ... and TMZ is streaming live.

Attorney Ben Crump is set to join Nolan's parents, Rep. Maxine Waters and Stop AAPI Hate Executive Director Cynthia Choi at a news conference Monday in Inglewood, California.

They’re expected to renew demands for a federal investigation into what happened to Nolan, who disappeared during a Fourth of July boating trip to Horn Island in Mississippi and was found dead two days later.

Nolan's cause and manner of death remain officially undetermined.

As TMZ previously reported, the state autopsy found bruising to the back of Nolan's head and neck, but no other external or internal injuries that explained his death. The report also said there was no fluid or debris in the airways of his lungs.

Nolan's family commissioned a separate autopsy, which they say found a much larger area of blunt-force injury to the back of his head, along with additional bruising on his back.

A Mississippi grand jury declined to bring criminal charges in the case, but Nolan's family has continued pushing for an independent federal review.

The case has also sparked a public dispute over some of the family's claims.

As we reported, United Cajun Navy leader Brian Trascher -- who helped find Nolan's body -- accused Crump's team of presenting some facts in a misleading way, including claims surrounding where Nolan's body was found and messages allegedly deleted from his phone.

The National Asian Pacific American Women's Forum is backing the family too ... saying Nolan's parents deserve "transparency, accountability, and the truth" and urging the DOJ and FBI to independently review the circumstances surrounding his death.