WARNING: THE CELLPHONE VIDEO IS DISTURBING.
The dog's owner was identified as Claudia Kelly, the adult daughter of former astronaut Mark Kelly. Mark Kelly is seen in the video pulling the dog away from the sea lion. But the sea lion died shortly after the attack on Saturday.
Officials say the sea lion had been tagged earlier in the day as a beached animal in distress.
"It was actually the stress of the attack that killed the sea lion and not the actual dog bites. The wounds from the teeth were only superficial in nature," said Jim Beres with Laguna Beach Animal Control.
Police say no crime was committed. A spokesman for Mark Kelly and his wife, former Rep. Gabrielle Giffords, issued a statement calling it "a sad accident."
KABC-TV Los Angeles, CA contributed to this report.