Vic murder accused made threats: court

An ice addict told his girlfriend his mission would be complete when she was gone two months before he shot her in the head, in what he says was a tragic accident, a Melbourne court has heard.

Nelson Lai, 35, said he was "just venting", "scattered" or "paranoid" when he repeatedly threatened to kill Rekiah O'Donnell, 22, in the last months of her life.

Lai told the Victorian Supreme Court on Wednesday he never would have pulled the trigger if he'd thought the borrowed gun was loaded on the morning of October 11, 2013.

He was waving it around his Sunshine bedroom, pulling the trigger, when he heard a bang, then a thump.

"I wasn't anticipating anything coming out of the gun," Lai said.

Ms O'Donnell was shot through the head and died.

Lai has pleaded not guilty to one charge of murder.

Under questioning from prosecutor Andrew Grant, Lai said he'd emptied bullets out before he started pointing the gun around.

Asked if he had noticed only five bullets came out, Lai said: No.

Lai said Ms O'Donnell had been in the bed with him only seconds before the gun went off.

"There really was no need for me to look where the gun was pointed," Lai said.

He denied he was angry, or in a rage due to coming down on ice, though he had smoked ice about 2am that morning.

The court had earlier heard Lai was abusive and threatening towards Ms O'Donnell during their 14-month relationship.

Mr Grant read from text messages between the pair in which Lai threatened to kill Ms O'Donnell, said he knew where her mother lived, and called her a "lying dog mutt c***".

In one exchange, Lai wrote, "My mission will be complete when you're gone, slut."

He also sent: "You're f****d, you're f****n dead slut," two months before she died.

On Wednesday, Lai told the court he became paranoid and jealous when smoking ice.

Mr Grant told the court Ms O'Donnell had written to Lai during a period of separation and pleaded with him to seek help from a domestic violence support service.

The letter, which included a support service brochure, said she never deserved his physical and emotional abuse, which included knives to her head, death threats and kicks to the stomach.

"You deserve so much more baby, so does the next woman who comes along," Ms O'Donnell wrote in the letter read to the court.

"You are sick and need help, even so, you are my babeh."

Lai cried as he was asked to look at photos of Ms O'Donnell after she was shot.

The trial continues before Justice Michael Croucher.