A family who brutally beat their daughter’s mother to death in their home has been sentenced to life in prison.

Fiona Button pleaded guilty in the Northern Territory Supreme Court on Friday to the murder of 23-month-old Kia Thompson, who was found dead on March 27, 2016.

The mother’s body was found at a house on May 6, 2016 in the Alice Springs community of Doolin, with the infant’s mother in the backseat.

Button pleaded guilty to the manslaughter of Kia’s mother, Kari Thompson, and a separate charge of the manslaughter and murder of her unborn baby.

Her victim’s family said in a statement they were “devastated” and “distressed” by the sentence.

“They’ve now had their day in court and we thank the courts for doing the right thing for us and for the family,” the family said.

Mr and Mrs Thompson’s mother Kari was found guilty of murder and was sentenced to seven years.

A statement from the Thompson family said Kari “did not deserve to die at the hands of the people who were responsible for her death”.

“Her parents were extremely proud of their daughter and the care that they gave her.

They will be forever indebted to them for their hard work,” the statement read.

It also said the Thompson children were devastated by the court case and the loss of their mother.

She had “an exceptional, strong personality and was a proud, caring mother who had no plans of returning to prison.”

The couple had been on a “very loving and loving relationship” with Kari’s father.

Kari’s mother said she was “sad to hear the news”.

The Thompson family also thanked the community for their support during the trial.

They had been supported by Kari and her siblings and a family friend. ABC/wires