Brandon Clarke's body has officially been cleared to be released to his family ... but the mystery surrounding his sudden death remains unclear.

According to the Los Angeles Medical Examiner's website, the ME has declared the NBA star's body ready for release, however his cause and manner of death is currently deferred ... pending additional testing as authorities investigate.

As we previously reported, Clarke’s death came just days before he was due in court to face multiple criminal charges, including trafficking a controlled substance and felony fleeing.

The Los Angeles Fire Department PIO confirmed to TMZ Sports they responded to a medical emergency call around 5 PM on Monday ... and when paramedics got to the scene, the 29-year-old male was declared deceased.

TMZ Sports confirmed his death is being investigated as a possible overdose ... with officials finding drug paraphernalia inside the home the Memphis Grizzlies player was staying at.

The Grizzlies released a statement Tuesday saying, "We are heartbroken by the tragic loss of Brandon Clarke" ... adding, "Brandon was an outstanding teammate and an even better person whose impact on the organization and the greater Memphis community will not be forgotten."