Updated

CHINO HILLS, Calif. -- Two Southern California brothers -- a 12-year-old who loved skateboarding and a 10-year-old about to start fifth grade -- were shot to death with their father's handgun in what could be a double suicide or a murder-suicide, authorities said Wednesday.

The bodies of Bryan Gonzalez and younger brother Christian Gonzalez were found Tuesday by a family member in a ravine behind their Chino Hills mobile home in rural San Bernardino County. The father's gun was found with the bodies.

Autopsies were planned Wednesday and gunshot wound information was being withheld by detectives and the coroner's office, sheriff's spokeswoman Jodi Miller said.

She said only the boys were involved in the shootings, though investigators were not sure whether they each killed themselves or one killed the other before committing suicide.

There were no suicide notes or details about trouble in the home the boys shared with their parents, Miller said.

Neighbors heard gunshots and deputies were called to the home, nestled in brushy hills about a mile up a poorly paved road about a mile from the boys' elementary school. The bodies were in a ravine about 60 feet from the family mobile home.

Detectives haven't disclosed if the gun had been locked up.

"It was the father's gun and that is something investigators will look into," Miller said, adding the father and mother have been cooperative.

Parents and classmates of the boys were devastated. Flowers, candles and a poster that had a photo of Bryan during his class trip this year to Disneyland were left near the home.

"It's just tragic. We're all just trying to make sense of it right now," said Robert Gavela, who stood at the end of the boys' street with his 13-year-old daughter Madison.

"It's crazy. It doesn't seem real," Madison said.

Bryan was going into seventh grade this fall. Friends said he dreamed of being a professional football player.