Celeste Rivas‘ family says they’re “devastated” by newly released autopsy findings … and confirm they won’t attend an upcoming hearing for D4vd, who’s charged with her murder.

The Rivas Hernandez family, through their attorney, tells TMZ … they’re suffering “profound emotional pain” after reviewing the report into their daughter’s killing … describing the details as “horrible and gruesome.” They’re now asking for privacy, understanding and patience as they process the tragedy.

The family also says Celeste’s parents, Jesus and Mercedes, will not attend D4vd’s hearing scheduled for Thursday.

We broke the story … the Los Angeles County Medical Examiner had actually determined Celeste’s cause and manner of death months ago — back on December 9 — but the findings were kept under wraps due to a court-ordered security hold requested by LAPD during the investigation.

Now that the info is public, L.A. County M.E. Dr. Odey Ukpo is speaking out … saying it’s “unfathomable” the grieving family had to wait so long for answers.

Ukpo emphasized transparency is critical not just for accountability, but to help communities understand and prevent future tragedies.

The M.E.’s report ultimately ruled Celeste’s death a homicide caused by multiple penetrating injuries from unspecified object(s).