The body of Brandon Clarke has been cleared for release to his family following the NBA star's death at 29.

But what killed the Memphis Grizzlies player remains unclear after the cause of death was 'deferred' by the Los Angeles medical examiner. 

According to TMZ, more testing will follow as the authorities probe his death, which sent shockwaves through the NBA.

The Canadian-American player was found dead in the San Fernando Valley, Los Angeles County, after fire crews responded to a 911 call of a medical emergency shortly after 5pm local time on Monday. 

Los Angeles outlet NBC4 reported on Tuesday that Clarke's death was being investigated as a possible overdose.

Paramedics are said to have declared him dead upon arrival at the scene, with drug paraphernalia found in the home. 

The Grizzlies confirmed his passing in an emotional statement in which Clarke was described as an 'outstanding' member of the Memphis community. 

'We are heartbroken by the tragic loss of Brandon Clarke,' the NBA team said in a statement. 'Brandon was an outstanding teammate and an even better person whose impact on the organization and the greater Memphis community will not be forgotten.

'We express our deepest condolences to his family and loved ones during this difficult time.'

Clarke, who joined the Grizzlies after being drafted with the 21st overall pick in 2019, died just four months before his 30th birthday. 

According to reports, the NBA star was soon due in court to face several charges including trafficking a controlled substance and felony fleeing.

It comes after he was arrested in Arkansas last month on charges including speeding and trafficking a controlled substance. 

The Cross County Sheriff's Department booked him into jail on April 1 for improper passing, possession of a controlled substance, fleeing and exceeding the speed limit and trafficking a controlled substance.

Clarke was in his seventh season out of Gonzaga and, in one of his final social-media posts, the Memphis player commented on a video shared three days ago by his barber, whose Instagram handle is @california_kingdoc.

'Love brotha !' he replied less than two days ago.

Tributes have poured in for Clarke following his death, including from NBA commissioner Adam Silver.

'We are devastated to learn of the passing of Brandon Clarke,' Silver said in a statement. 'As one of the longest-tenured members of the Grizzlies, Brandon was a beloved teammate and leader who played the game with enormous passion and grit.

'Our thoughts and sympathies are with Brandon's family, friends and the Grizzlies organization.'

The National Basketball Players Association also wrote in a statement: 'We are heartbroken by the tragic passing of our brother, Brandon Clarke. 

'This is an incredible loss for the brotherhood. We will remember Brandon not only for the immense joy he brought to so many throughout his career, but for the genuine friendships he built far beyond basketball. Our deepest condolences go out to Brandon’s family, friends, and teammates during this difficult time.'