McInerney is being tried as an adult in the killing of a gay classmate at an Oxnard middle school. McInerney's aunt was on the stand Thursday.
Brandon McInerney's aunt, Megan Zorba, spent most of the day on the witness stand. Zorba told the jury that McInerney's father physically abused him as a child. She said William McInerney would sit on his son until he couldn't breathe, pull his thumb back until he screamed and punch him in the face.
McInerney looked angry as his aunt described the abuse.
Others have testified McInerney's cousin Kyle abused him.
McInerney is charged with murder with a hate-crime enhancement for the 2008 shooting death of 8th-grade classmate Lawrence King in a classroom at E.O. Green Junior High School. Prosecutors maintain McInerney killed King because he was gay.
Defense attorneys are arguing that McInerney's troubled childhood was part of the reason he shot King to death.
On the witness stand, Zorba told the jury Willliam McInerney would often physically and verbally abuse his son when he was drunk or on drugs.
"He was more combative under the influence," said Zorba. "He would like to play practical jokes and be meaner when he was under the influence. You know, pick on him, push him, sitting on him, not getting off of him till he can't hardly breathe. He liked to mess with him, hard."
Kyle McInerney, Brandon's cousin, is expected to testify Friday.