Queensland Police have received new information about the disappearance and suspected murder of in the state's north more than four years ago.
The 15-year-old was last seen in the town of Ayr and was possibly travelling to Townsville in March 2019 "in the company of relatives and associates".
Detectives said on Monday they had received details suggesting an altercation occurred within the group and a firearm was used, resulting in his death.
Police are investigating whether his death was deliberate or accidental.
Child Protection Investigation Unit officer Dave Miles said an "independent and reliable witness" had provided information about an interaction with the teenager before his disappearance in 2019.
"During this interaction, Linden told the witness he was in fear for his life, and he had 'come to say goodbye'," Senior Sergeant Miles said.
"The witness urged Linden to speak to the police but Linden stated: 'No one could help me now'."
Sen Sgt Miles made a public appeal in light of new information being presented to police, to bring closure to the teenager's family.
"We now know that there are other people who have knowledge of what occurred. We know there are people involved in the transportation of Linden to Townsville and were probably with him in and around the time he disappeared," he said.
"And it's a matter of those people coming forward to give us information to progress this investigation."
In March, police announced a $500,000 reward to help solve the suspected murder of the 15-year-old.
"It is important the community rallies together to bring Linden home," Sen Sgt Miles said in a statement on Monday.
"Linden's family has not given up hope and deserves answers."
