Witnessing child abuse (California)

[ssfsx17]

I'm from Alameda County, California

I was loitering at a public park late at night (10:00pm). I witnessed a mobile home driving into the area, followed by a couple and their daughter disembarking from it and entering the park. I witnessed the man of the family being very drunk and shouting very loudly. I did not observe them visually, but I clearly heard a large "WHOP!" sound followed by his daughter crying, multiple times. Ten minutes later, they went back into their vehicle and drove away. I did not get a good look at their vehicle, nor did I note its license plate.

Should I have taken a picture? (I did possess a cell-phone camera)
Should I have called 911?
How quickly could the police respond?
Is this common among families that live in mobile homes?

[retdetsgt]

Yes to both first questions. The police would respond as quickly as possible. They would check the child for injuries and go from there. Spanking a child is one thing, injuring a child by beating them is something else.

Child abuse is often more predominant in poorer families although it does run the spectrum of society.