Schmidt's defence, led by high profile Perth QC Tom Percy, sought a sentence of less than life.
Justice Ralph Simmonds deferred Schmidt's sentencing until Monday while he considered matters including an unrelated 2010 case where a sentence of less than life was sought for murder.
That application was unsuccessful.
Mr Marshall's father Alan flew to Perth for both the trial and sentencing, and today read out in court a victim impact statement in which he spoke of the devastation of losing his son.
His wife, Wendy, and daughter and son also delivered victim impact statements via videolink from New Zealand.
Outside the court, Mr Marshall said he would accept whatever sentence was handed down.
-AAP