The David Eastman saga shows the dangers of "tunnel vision" constraining a police investigation, a leading barrister says.

The Australian Federal Police are remaining tight-lipped about the findings of the Eastman inquiry, released on Friday.

ACT Bar Association president Barrister Greg Stretton, SC. Credit:Rohan Thomson

The inquiry found that investigating police, at times, crossed the line into “unlawful and unfair” conduct, while acknowledging they were operating in an extremely challenging environment.

Police harassment included verbal abuse, aggressive confrontations, repeatedly surrounding Eastman and invading his personal space, and forcing an interview on him when he was in custody on another matter, despite clear advice he wished to exercise his right not to speak about the murder.