WA murder accused intended 'warning shot'

A swinger who shot his "servant" de facto wife in the face and then lied to police that she had taken her own life only meant to fire a warning shot, a Perth court has heard.

Robert Jeffrey Anderson is on trial in the West Australian Supreme Court charged with the murder of Phaea Leanne Lightfoot, 51, who was found dead in the couple's Wanneroo home on August 29, 2012.

Defence lawyer Gary Massey said in his opening address on Tuesday that Anderson admitted he lied to police and the triple zero operator that Ms Lightfoot killed herself.

Mr Massey said Anderson intended to fire a warning shot at the bedroom doorway after she threw a ceramic cat at him during an argument.

But Ms Lightfoot moved into the doorway and was shot in the chin, killing her instantly.

Prosecutor Nick Cogin said Anderson snapped after Ms Lightfoot annoyed him too many times.

Mr Cogin said Anderson placed the gun by Ms Lightfoot's body, mopped up the blood with towels "so he wouldn't slip" and put them in the washing machine.

During the emergency call, which was played in court, Anderson said Ms Lightfoot shot herself after he told her "she didn't have the guts" to do it.

He also told the operator she had taken the keys to the gun safe weeks ago - which the court heard he had also previously claimed to Ms Lightfoot's brother.

Anderson told the operator Ms Lightfoot was "mental" and a speed addict, but also his one true love and that he had her name tattooed on his chest.

"Why did you do this, you stupid girl?" he said.

"I thought she was f***ing around. I didn't even know she had put shells in it."

Mr Cogin said the couple were in a volatile relationship and the argument that led to the shooting was sparked by the highly sexualised Ms Lightfoot's long-running anger that Anderson could not perform for her sexually.

He said Anderson was the dominant party in the couple's servant-master relationship, which was known to the family, and the pair attended a swingers club.

Mr Cogin said a month before the shooting, Anderson texted Ms Lightfoot's daughter that he was worried one of them would snap and if it was him, that he would seriously harm her.

"I'm at my wits end. She calls me a c***, a blob of useless s***," the text read.

"It's getting close to explosion time."

Mr Cogin said Anderson was an experienced shooter, and while Ms Lightfoot's attitude to him may have been reprehensible, it was unnecessary to fire the gun.

The trial continues.