Three post-mortem photographs of slain NSW policeman Bryson Anderson have been tendered in court as evidence as his alleged killers face a committal hearing.

Detective Inspector Anderson, a 45-year-old father of three, died after he was fatally stabbed while trying to calm a neighbourhood dispute over a bird cage in Oakville, in Sydney's northwest, on December 6 last year.

Fiona Barbieri, 45, and Mitchell Barbieri, 19, have been charged with his murder.

On Monday, the pair fronted Sydney Central Local Court for the start of a four day committal hearing into the killing, which Magistrate Christopher O'Brien adjourned until Wednesday.

Both accused showed little emotion in the brief hearing during which volumes of written evidence, nine DVDs showing police "walk-throughs" of the crime scene, and three post mortem photographs were tendered as evidence.