A high-ranking Queensland police officer has been cleared over allegations of misconduct during investigations into the disappearance of Daniel Morcombe.
Assistant Commissioner Mike Condon was investigated by the Queensland corruption watchdog for his role in alleged corrupt and criminal conduct, including perjury.
Among the probe, the Crime and Corruption Commission looked into his handling of the investigation into the Sunshine Coast schoolboy's 2003 disappearance and claims he reportedly tried to prevent two detectives giving evidence into Daniel's inquest.
Former detective Dennis Martyn told the inquest in December 2016 that two weeks after Daniel went missing, he identified Brett Peter Cowan as a main suspect but had been ignored.
During the inquest into Daniel's death, Mr Martyn said Mr Condon told him to "f*** off, you wouldn't know anything" when he said he believed Cowan was the man responsible.
His partner Kenneth King also testified he had considered Cowan a key suspect but the lead was not immediately pursued.
Mr Condon told the inquest the conversation with Mr Martyn never took place.
The Queensland Crime and Corruption Commission (CCC) received the allegations in December 2016 before referring them to the police's Ethical Standards Command.
Some of the allegations were sent back to the CCC, which conducted 35 interviews with past and present police officers and examined electronic data including emails.
The CCC also looked into transcripts from the inquest as well as evidence given at two of Cowan's hearings before finding there was no case for accused police to answer.
"Based on all the material examined and the broader investigation, the CCC has determined there is insufficient grounds for the consideration of any criminal prosecution or disciplinary proceedings in relation to the allegations," the CCC said in a statement on Wednesday.
Cowan was convicted and sentenced to life in jail in March 2014 for murdering the 13-year-old.
His arrest came after an elaborate sting operation involving police from three states coaxing him into confessing to undercover officers, who he believed were gangsters.