I Heard an Animal Attack Another Animal in My Backyard in San Diego, Do You Know What Kind It Was?

I live in San Diego above a canyon with a freeway below the canyon (across the freeway from SDSU,not exactly rural). Last night I heard an animal being attacked by another animal but it was dark and hard to see. I could see one much larger animal that appeared to be around 40lbs, and round looking (like an overgrown possum). The other animal was making a horrible, screaming, warbling sound. Does anyone know what these animals may have been?