In just a few hours the jury found the 69-year-old not guilty

The defense questioned whether the sexual intercourse was consensual

DNA samples prove the son was in fact Mr O'Connell's, prosecution said

The son persuaded the woman to go to police, sparking an investigation

A man has been found not guilty of raping a 16-year-old girl 49 years ago, after investigations began in 2013 when the son conceived during the encounter was reunited with his mother.

John Thomas O'Connell, now 69, from Moama on the border of Victoria and New South Wales, was charged after the adult son of the pair who was put up for adoption tracked down his mother.

When the birth mother told her son the story of his conception, he persuaded her to go to the police, the Bendigo Advertiser reported.

However a jury found Mr O'Connell not guilty on Tuesday afternoon, taking only a few hours to reach their verdict at Bendigo Country Court.

Mr O'Connell was accused of having non-consensual sex with the plaintiff in January 1967 when she was 16 and he was 20, leading to the conception of their son.

The prosecution alleged Mr O'Connell dragged the teen into bush land and raped her.

However, the jury could not rule that the sex had been non-consensual.

John Thomas O'Connell leaves the Bendigo County Court after a hearing in October. He has pleaded not guilty to the rape of a 16-year-old girl in 1967

Outside court Mr O'Connell told the Bendigo Advertiser 'I am very pleased with the verdict, I'm pleased it's over, it's been a long 19 months. I can move on with my life.'

The accused was finally found not guilty on the fourth attempt after the first jury was thrown out due to a clerical error in October, the court was delayed due to concerns of prejudice in December and a jury was discharged again in February after failing to reach a unanimous decision.

Two weeks ago Mr Hoare, in his opening to the jury, said the son was 33 when he found his birth mother in 2000 and she told him how he was conceived, WA Today reported.

While their offspring's parentage was not in dispute due to prior DNA testing, defence barrister Michael Pena-Rees told the jury that what needed to be proven was whether consensual sexual intercourse happened, as well as details of how and where it took place.

Defence barrister Michael Pena-Rees told the jury that the real issue was whether the sexual intercourse was consensual, and the details surrounding that.

The woman was living in Rochester with her mother and siblings at the time.

Mr Hoare told the court that at 8pm in late January in 1967, the victim was walking with friend Valda Grogan across Campaspe Bridge when Mr O'Connell and another man approached them in a big black car.

Despite a nearby dairy worker cautioning the pair to not get into the car, Miss Grogan jumped into the back seat against the victim's wishes.

She was eventually convinced to climb in when the driver allegedly said, 'Look, just get in, jump in the front seat. We're going to see a mate around the corner and we'll drop you home.'

Bendigo County Court where Mr O'Connell is currently standing trial for an alleged rape 49 years ago

Mr Hoare said she did not know the make or model of the car, but remembers a white doll on a lace cushion sitting in the back window.

They drove out of Rochester and stopped after the victim started yelling that they were going in the wrong direction as they began to travel out of town.

The prosecution alleges Mr O'Connell dragged the victim from the car as she struggled to escape, then pushed her underwear to the side and had sex with her.

'She'll say she was fighting him, trying to get away from him, but he was too strong for her,' Mr Hoare said.

'She'll certainly say she was not consenting,' Mr Hoare said.

After the alleged rape 100 metres away from where he dragged her, the victim and Miss Grogan were dropped home.

The victim confided in only one friend, Jacqueline Sinclair, who then urged her to tell police.

Ms Sinclair, who at the time was married with two children, told the victim's mother, but no report was made until the victim moved to Melbourne soon afterwards to find work.

The victim was unaware she was pregnant until five months later when her mother arranged for her to stay at 'The Good Shepherd' convent in St Kilda, where a compulsory medical assessment revealed she was expecting.

She initially denied she had ever had sexual intercourse. Nuns, however, took the matter to the police but it was not investigated and they allegedly called her a 'liar'.

The woman later saw Mr O'Connell at a dance in Moama and spoke about him with a friend who was with her. The friend made a statement - which cannot be found - to police years later and gave a statement at the trial.