David Eastman, who spent nearly 20 years in jail over the killing one of the country’s top police officers, has been found not guilty of the murder after a retrial.

A jury determined Mr Eastman did not murder senior Australian Federal Police officer Colin Winchester nearly three decades ago.

The not-guilty verdict in the ACT Supreme Court marked the end of a six-month trial and nearly a week of deliberating.

Mr Eastman spent 19 years in jail after a first trial found him guilty of shooting Mr Winchester as he got out of his car near his house in 1989.

But a 2014 inquiry found flaws in the original forensic original evidence had lead to a miscarriage of justice, causing Mr Eastman to be tried a second time.

The ACT Government had invested millions in proceedings against Mr Eastman, allocating dedicated funding in recent territory budgets.

Taxpayers forked out $6.5 million for this year’s re-trial.

In the past decade, additional legal proceedings surrounding the trial cost upwards of $30m.

More to come.

-ABC