Isaac Costa pleads guilty to murdering fiancee Anastasia Slastion at Greystanes in 2023

A man has admitted murdering his new fiancee at his family’s home in western Sydney days after introducing her to his friends. Read the latest from court.

Anastasia Slastion’s fiance has admitted killing her. Picture: Nine News

A man has pleaded guilty to murdering his new fiancee at his family’s Greystanes home in 2023 after the woman had moved to Australia from Russia in search of a better life.

Isaac Costa, 30, killed Anastasia Slastion on Saturday, February 25, at the Costas’ Brighton St home.

Neighbours said they woke in the early hours of the morning to a “screaming fit”.

Police found Ms Slastion dead in the home, owned by Costa’s father Clem, in the early hours of the morning after she was reportedly beaten to death.

Paramedics were called to assist Ms Slastion but her injuries were too severe and she could not be revived.

Anastasia Slastion was a software engineer. Picture: Facebook

Isaac Costa faces sentencing in July. Picture: Facebook

“He was there four days ago introducing her to everyone as his new fiancee,” a neighbour said after the incident.

“She had a thick Russian accent. It’s just so sad that this has happened days later.”

Ms Slastion was murdered at Brighton St, Greystanes. Picture: Nine News

Detectives under Strike Force Alimah were investigating if they had met via a dating app.

At Parramatta Local Court on Thursday, Costa, with a neat haircut and wearing a polo prison green shirt, appeared briefly via video link as the court heard he would plead guilty to domestic violence-related murder.

The case was adjourned to the NSW Supreme Court for sentencing on July 4, when he will also front court via video link.

The court heard there was a matter of dispute in the police fact sheets that will be determined in the Supreme Court.

Costa introduced his friends to his fiancee before killing her four days later.

The victim’s extended family across Europe and Russia paid tribute to the “beautiful, super-intelligent, talented girl” shortly after her death.

Her cousin Violeta Samsonova said the family was struggling after the tragedy.

“This is such an emotional pain for our family,” she said in an online post.

She said she could not believe Anastasia was gone.

“She was such a beautiful, super-intelligent, talented girl,” Ms Samsonova said.

“She had her whole life ahead of her.”

Another relative of Ms Slastion said she had worried about her being alone in Australia without any friends or family.

Police at the scene of the murder on February 25, the day of the murder. Picture: Julian Andrews

At his first court appearance a day after the murder, Costa’s dad expressed his support for his son when he said he would always love him.

The property where the homicide occurred was a series of small cabins and a caravan on a lot next to a childcare centre. Mr Costa owns the cabins.

Ms Slastion was one of 58 women who were victims of domestic violence homicide in NSW in 2023.

Across Australia, that figure was 64 in the same year.

Under a NSW program to be rolled out, police will be empowered to remove perpetrators from the home while victim-survivors receive support.

That means domestic violence victims will no longer be forced to escape their homes under the new protection program that will focus on fortifying their properties while their abusers instead move out.