BRENTWOOD (CBS) — Sage Stallone was laid to rest Saturday.

The 36-year-old son of actor Sylvester Stallone died last week.

The private funeral service was held this morning in Brentwood at St. Martin of Tours Catholic Church.

The media was kept at a distance, but witnesses said Sylvester Stallone, wife Jennifer Flavin, his brother Frank, Sage’s mother Sasha Czack, Sage’s siblings and family members and friends attended.

The family asked, in lieu of flowers, that donations be made to Autism Speaks. Sage’s younger brother, Seargeoh, is autistic.

Circumstances surrounding the death are still under investigation.