WA man guilty of killing his ex-girlfriend

A man has been found guilty of brutally murdering his former partner, whose naked body was found lying on a mattress in her West Australian home.

Kevin James Corbett killed 36-year-old Charmaine Winmar at her Narrogin home, in the Wheatbelt region, in May 2013.

The 51-year-old caught a bus from East Perth to Narrogin, leaving abusive graffiti related to Ms Winmar along the way, before attacking her in her home, the court heard.

Ms Winmar died from multiple head and chest injuries after the bashing in which several weapons may have been used.

Her partner, Richard Penny, was also injured in the attack and was asleep or unconscious when police arrived, the court heard during the trial.

But Corbett's lawyer Richard Utting had suggested Mr Penny, who was living with Ms Winmar and had previously been convicted of punching her, could be an alternative suspect.

A jury convicted Corbett on Wednesday in the WA Supreme Court.

Justice Stephen Hall has ordered a psychological and psychiatric report before a sentencing hearing in July.