Former constable Zachary Rolfe was acquitted of murdering Kumanjayi Walker, 19, who he shot three times and killed during a bungled outback arrest at Yuendumu in November 2019.
The decision to charge Mr Rolfe four days after the shooting sparked outrage in many members of the NT police force and community, which continues today.
After his five-week trial ended in March last year the NT Police Association, opposition politicians and Mr Rolfe's legal team alleged the then chief minister, Mr Gunner politically interfered in the decision to arrest the former policeman.
A central feature of the allegations was Mr Gunner's address to the Yuendumu community three days after Mr Walker was killed when he said "consequences will flow" while explaining the role of a coroner.
The comments triggered an investigation by the NT's Independent Commissioner Against Corruption Michael Riches into the four days between the shooting on November 9 and November 13, when Mr Rolfe was arrested and charged.
Mr Riches on Thursday tabled a 31-page report to parliament that dismissed the allegations and found Mr Gunner had not interfered in the decision to lay charges.
"The former chief minister did not intend to prejudice the administration of justice, nor to influence the police investigation," Mr Riches said in the report.
"Rather, I find that when making the comments, the former chief minister was endeavouring to address matters that had been raised with him during the all-male meeting with elders and matters that he understood were of concern in the community."
He said Mr Gunner's conduct did not involve illegality, corruption, impropriety, incompetence or negligence.
"It is clear on the evidence that the former Chief Minister's comments had no impact or influence on the decision to arrest Mr Rolfe."
During his address to the Yuendumu community, Mr Gunner said the coroner was a judge, explaining the investigation would be "thoroughly independent".
"I know the coroner will listen to you and the coroner will seek to answer those questions that you have, those questions that I have - what happened that night," he said.
"I can promise you that that investigation will be independent and that consequences will flow as a result of that investigation."
Mr Riches said that while there was no finding of impropriety against Mr Gunner he did not doubt his comments caused anger and frustration among police.
He also said Mr Gunner's Yuendumu address and the phrase "consequences will flow" was directed towards a coronial inquest.
Mr Riches also investigated a rumour and allegation that police facilitated a secret meeting at a hotel between the former police commissioner Jamie Chalker, Mr Gunner and the then deputy chief minister Nicole Manison during the investigation into Mr Walker's death.
He said one version of the allegation was that the alleged meeting was facilitated by a senior police officer. Another was that the meeting was facilitated by a member of the NT Police Tactical Response Group.
"The assertion arose from third-hand information ... (and) in my view, this was a rumour without substance," he said.
"Being satisfied that no further inquiry was warranted, I find that no such meeting took place."
