A pregnant woman said she had been hit in a call to emergency services shortly before actor Ryan O'Neal was arrested.
Ryan O'Neal was bailed after five hours in detention
In recordings released by the Los Angeles sheriff, JoAnne Berry, a friend of Mr O'Neal's son Griffin, says she "can't see" and asks for an ambulance.
Ms Berry does not say in her call who hit her or the object used.
Mr O'Neal, 65, was arrested on suspicion of assaulting Griffin with a handgun during a family dispute, and negligent discharge of a firearm.
He was released on bail after five hours in detention.
The district attorney's office, which will decide whether Mr O'Neal should face charges, said it has not yet received the case.
Mr O'Neal found fame in 1960s US soap Peyton Place and went on to star in films like Love Story and Paper Moon.
The dispute came after he, actress Farrah Fawcett and some friends returned from a dinner celebrating her 60th birthday.
In a statement, the actor said his son, Griffin, was at the house and began "wildly swinging a fireplace poker".
Griffin grazed him four or five times and "aimed at my head, I ducked, he hit his own girlfriend in the head," O'Neal said in an interview published in the Los Angeles Times.
"I got a little nervous at that point and fled to my room and I got my gun," he said.
O'Neal had a 15-year relationship, and a son, with Fawcett
"I just fired it into the banister, and that scared him and he fled."
Ms Berry was slightly injured in the incident and treated at a hospital and released, said the star's manager, Neil Hassman.
But Mr O'Neal's daughter, Tatum, has denied this version of events.
"No matter what my dad is saying in the press, Griffin was not trying to start a fight with him," she told US TV show Entertainment Tonight.
The actress claims Griffin was attempting to protect her half-brother, Redmond - Mr O'Neal's son from his relationship with Ms Fawcett.
Griffin, whose own acting career never took off, is Ryan O'Neal's son from his first marriage, with Joanna Moore.
He was given an 18-day jail sentence for not performing 400 hours of community service after being found guilty of reckless boating in a 1986 accident that killed director Francis Ford Coppola's son Gian-Carlo Coppola.
In 1989, he also pleaded no contest to a drunken driving charge and was sentenced to probation.
And in 1992, he pleaded no contest to charges that he shot at his estranged girlfriend's unoccupied car.
At the time, he agreed to spend a year in a drug rehabilitation programme and serve five years on probation.