David Harold Eastman had been optimistic about his future in the days before Colin Winchester’s murder, his defence says.
The former treasury official believed his prospects of re-entering the public service within six months were good and hoped to have assault charges - listed to appear in court on January 12, 1989 - against him dropped.
"What would be achieved by acting before the 12th of January? It would not mark the end of the line," George Georgiou, SC, told an ACT Supreme Court jury on Tuesday.
Australian Federal Police Assistant Commissioner Mr Winchester was shot dead, at close range, in his car after he had pulled into his neighbour's driveway about 9.15pm on January 10, 1989.
Mr Eastman, 73, has pleaded not guilty to the murder.
The Crown alleges Mr Eastman murdered Canberra's most senior police officer in an act of revenge for what he saw as the injustices committed against him.
Mr Eastman had spent years attempting to return to the public service when he was accused of assaulting a neighbour, a charge prosecutors claim he feared would ruin his chances of returning to work and which developed in a murderous hatred of police.
However, Mr Georgiou said his client had actually expressed optimism and hopefulness about the future during a visit to his doctor days before the assassination.
"That was a state of mind which existed despite the charge," the silk said.
Mr Georgiou asked jurors to think what possible purpose shooting Mr Winchester could have to promote Mr Eastman’s return to the public service or to effect the outstanding assault charge.
He said the assault case would still be marked for hearing, despite Mr Winchester's death.
Mr Georgiou also pointed to evidence that Mr Eastman, when questioned the day after the shooting, told police he had been out between 8pm and 10pm, but could not provide his whereabouts.
The defence barrister said the Crown alleges the defendant went to extreme lengths to get a gun, obtain Mr Winchester's address, surveil the property, and change his appearance before the shooting, yet did not plan an alibi and volunteered he had been out in the window the police chief had been shot.
"It doesn’t make sense," Mr Georgiou said.
The silk also said Mr Eastman did not have to speak to police and could have exercised the right to not answer any of the questions of the police.
The trial continues.
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