Police confirmed the remains, believed to be Pheobe, were found about 2.30pm on Friday near Good Night Scrub National Park, southwest of Bundaberg in Queensland.
Pheobe's mother Kylie Johnson was quick to share her grief.
"I didn't think my heart could break anymore then it did when you went missing, or when the charges were laid but this! This is ripping me apart ..." she posted on Facebook.
Detectives have set up a crime scene where the body was found and continue to appeal for further information.
Earlier on Friday Pheobe's sister Kaylea Bishop issued a heartbreaking plea to find her sibling outside a southern Queensland court where James Wood, 34, and Tanika Bromley, 33, were remanded in custody.
Pheobe's two housemates have been charged with murder and two counts each of interfering with a corpse.
They were arrested on Thursday night, marking three weeks to the day since the 17-year-old missed a flight and vanished.
Pheobe's sister was flanked by supporters at Bundaberg Magistrates Court, where Wood and Bromley's matter was mentioned on Friday.
Locals gathered outside court including one holding up a sign in support of the missing teen's shattered family as Pheobe's sister launched her tearful appeal.
"If you've got any information about Pheobe ... just come forward," she told reporters.
"Three weeks is too long for us as a family. We just want her home.
"She was loved, she's missed dearly."
Police allege Wood and Bromley moved Pheobe's body more than once.
"Whilst we always hoped to find Pheobe alive, our investigation ... quite clearly showed us that that was not going to be a viable outcome," Detective Inspector Craig Mansfield said.
Pheobe was last seen near Bundaberg airport about 8.30am on May 15 after booking a trip to Western Australia to see her boyfriend.
Wood and Bromley were housemates with Pheobe at a Gin Gin property near Bundaberg.
Police allege the pair drove the 17-year-old close to the airport in a grey Hyundai but no one exited the car.
Pheobe was allegedly murdered and her body moved more than once from the Good Night Scrub National Park, an hour's drive from the airport.
Police had previously searched the park, saying their investigations indicated evidence may have been moved before officers arrived.
Phone data had led to officers focusing their search on the park, police said.
Police believe they understand the motive for Pheobe's alleged murder, the detective said.
Wood's SUV has been seized by police for forensic examination.
He had been living in the vehicle after the Gin Gin property he shared with Bromley and Pheobe was declared a crime scene following the teen's disappearance.
Police bodycam footage released on Friday showed the moment Wood was arrested in the Bundaberg area, with an officer telling him he was being taken into custody over the "homicide" of Pheobe.
Wood and Bromley have been remanded in custody ahead of their next court appearance on August 11.
They had earlier been charged with unrelated weapons offences after police allegedly found a shortened firearm, ammunition and two replica handguns in their car and home.
The Gin Gin community is set to hold a vigil for Pheobe in coming days.
"It's a sad day for the community and a devastating one for Pheobe's family," Bundaberg Mayor Helen Blackburn told AAP.
9°C