A series of controversial text messages that may have influenced Constable Zachary Rolfe’s defence to a murder charge were not meant for him, an inquest has been told.

Const Rolfe fatally shot Kumanjayi Walker, 19, three times as he resisted arrest in Yuendumu, northwest of Alice Springs, on November 9, 2019.

Afterwards, Const Rolfe received text messages telling him to justify his intent as self-defence against “the s*** c*** (who) was telling him that he was going to stab the police”.

But Sergeant Ian Nankivell, who wrote the messages, told the inquest into the fatal shooting he “emphatically denied” that the messages were for Const Rolfe.

Sgt Nankivell had sent the messages to a close friend of Const Rolfe, Constable Mitchell Hansen.

In November, Const Hansen told the inquest that Sgt Nankivell had sent the messages to him to forward to Const Rolfe.

The messages outlined an acronym “IAMO plus P” standing for intent, ability, means, opportunity and preclusion, that Patrick Coleridge, counsel assisting the coroner, said could be seen as a template for justifying Const Rolfe’s shooting of Mr Walker. 

Sgt Nankivell said the acronym had been part of his police force training in Victoria.

“It’s nothing about justification, it’s about mental health,” he said on Thursday.

When asked about his use of the word “critics” in the text messages, he said it referred to self-criticism, not external critics. “The IAMO plus P is designed just to guide you through the process (of thinking) when your mind is full fog and dread,” he said.

The messages were never intended to be seen by anyone other than Const Hansen, he said, despite also acknowledging that he was not close to Const Hansen nor did they have any relationship outside work. 

Const Rolfe was found not guilty by a Supreme Court jury of Mr Walker’s murder.

The inquest in Alice Springs continues, with other members of the NT Police Force, including Assistant Commissioner Bruce Porter, expected to give evidence over the next two weeks.