Two men have been charged with murder, accused of beating a Sydney woman to death with a baseball bat and rock before setting her body alight.
Police were called to an area near Sandy Point Quarry in Menai, south of Sydney, last July after a member of the public found Najma Carroll's body.
On Tuesday, detectives arrested a 57-year-old man at Silverwater jail and charged him with her murder.
On Wednesday, they charged a second man, 43, also at the prison.
Both will appear at Sutherland Local Court via video on Wednesday.
Homicide Squad Commander Detective Superintendent Danny Doherty said police believe Ms Carroll was murdered 15 days before her body was found.
It will be alleged the two men were associates the former honours student made after she began taking drugs.
The men were staying in the same Casula hotel-motel as the 33-year-old in the lead up to her death and took Ms Carroll to the bushland where her body was found.
There they beat her with a baseball bat and a large rock, causing massive head injures, police will argue in court.
Her body was then set on fire in an attempt to hide evidence.
"It's a horrific crime, it couldn't be any more brutal," Det Supt Doherty told reporters.
"It speaks volumes at the type of people these are.
"These are miscreants of society.
"They are just violent and malevolent people and had complete disregard for human life."
Ms Carroll's family thanked police, saying she would be remembered as a beloved daughter and a loving, generous and courageous spirit.
"Najma struggled with addiction from her teenage years but she never resorted to crime to feed that addiction," her mother said.
"We need to educate our sons and daughters that violence towards women is not acceptable and that culture needs to change."