Authorities say an autopsy found no obvious trauma in the death of a 20-day-old baby boy whose body was found in a swampy area near the Sacramento River in Northern California.

The Yolo County Sheriff's Office says Thursday's autopsy shows Justin Rees was apparently in good health.

There were no obvious physical injuries or signs of abuse, though he had minor scratches that could have come from the brushy area where he was found. It's near a rural town about 30 miles west of Sacramento.

The autopsy didn't rule out drowning or hypothermia, but additional testing could take months.

The infant and his 23-year-old mother, Samantha Green, of Woodland, were reported missing Monday.

She was found alive and disoriented Tuesday, and the baby's body was discovered Wednesday.