I should have given her roses: Qld killer

A man who bashed a Korean woman to death in a Brisbane park told her family he wished he could take it back and give her a bunch of flowers instead.

Alex Reuben McEwan has pleaded not guilty to murdering Eunji Ban on November 24, 2013, but guilty to a lesser offence of manslaughter on mental health grounds.

During his trial on Friday, the court heard details of letters McEwan wrote to the 22-year-old's family after he bashed her so severely she drowned in her own blood.

"I can't explain how sorry I am for your loss," McEwan wrote to the woman's grieving relatives.

"I wish I could take it all back and give her a bunch of roses instead. I will be praying for you."

Prosecutors allege McEwan repeatedly punched Ms Ban in the head and dragged her feet first up a flight of stairs leading from Albert Street in Brisbane's CBD to Wickham Park.

In a letter to his own family, which has also been read to the court, McEwan said he was ashamed of what he had done, but believed he was possessed when he attacked Ms Ban as she walked to work.

"I'm not sure if I will be able to look you in the face ever again because of what I've done to that innocent lady," he wrote.

"I will probably change my last name so that I am not a McEwan anymore because McEwans don't do murder."

He said he was sure he was bewitched by a demon at the time because he could not remember what happened.

"Don't forgive me, don't think of me ever again," he wrote.

Paramedics have told the court they were unable to immediately determine her gender due to the severity of her head injuries.

A pathologist who examined Ms Ban's body told the court on Friday the woman, who stood at 163cm, was covered in scratches and blood.

Dr Alex Olumbe said she had fractures to her face, bloodstains on her clothes and blood in her stomach.

McEwan will take the stand on Thursday when his trial resumes.