A killer who claimed a knife accidentally impaled his girlfriend in the neck had a history of violence against women, including pushing another partner while in her wheelchair into oncoming traffic, the WA Supreme Court is told.

WATCH THE VIDEO ABOVE: Christopher Thomas Dimer jailed over Nollamara murder. The court heard Dimer, a serial domestic violence offender, had thrown scissors at his partner of four years, punched her in the face and stabbed her in the neck with a knife. Headland, 26, died from her injuries.

A man who fatally stabbed his partner — but claimed he was trying to catch the knife as it fell from a window frame — admits he was violent but still does not accept he killed her.

Christopher Dimer tried to convince a jury a knife that was holding up a curtain had fallen and impaled his partner of four years, killing her.