Defence lawyers for the Queensland man accused of killing the McCulkin family in the 1970s have attacked the reliability of the key witness, saying he lied to “save his own neck”.

Garry Dubois, 69, has pleaded not guilty in the Supreme Court in Brisbane to murdering of Brisbane woman Barbara McCulkin and her two daughters Vicki and Leanne in 1974.

He is also accused of raping one of the girls and being complicit in the rape of the other.

The court heard the case centres on the reliability of the evidence given by Dubois’ criminal associate Peter Hall, who previously told the court Dubois confessed to him in the days after the family disappeared.

Dubois and his co-accused Vincent O’Dempsey took the McCulkins to bushland, where Ms McCulkin was separated from her daughters and strangled, Mr Hall said during the trial on November 10.

The daughters were then murdered, he said.

Defence barrister Dennis Lynch said the jury cannot convict his client on questionable evidence.

“What this case is all about is the reliability of Peter Hall,” Mr Lynch told the court.

“It’s abundantly clear that Peter Hall has told lies, it’s abundantly clear that he continued to lie.

“His reason for telling a lie was to save his own neck because it had been made painfully obvious to him that he wasn’t believed.

Mr Lynch also questioned the reliability of evidence given by other witnesses, who were young girls at the time the McCulkin family disappeared.

He said the young girls gave different statements to police when they were questioned in 1974 about what they noticed at the Highgate Hill house.

“The fundamental rules determine the correct starting point and the correct starting point is a presumption of innocence, not an assumption of guilt looking for anything that might help us get to that end point,” Mr Lynch said.

“We don’t convict people on policeman’s hunch or a whim or on the basis of suspicion or the flip of a coin, but only where a jury having heard all of the evidence can say for themselves, ‘I am satisfied to that high standard beyond reasonable doubt’.”

Prosecutor David Meredith told the jury it is an “extremely strong circumstantial case” showing Dubois was at the house on the night of the disappearance.

“Hall has no reason to tell you a false story against his friend,” he said.

“He has no reason to make it up.

“There is no evidence suggesting that someone else did it.”

Mr Meredith said Dubois might not have liked what was occurring but he was a participant in it.

“His presence is an encouraging presence, not a neutral presence,” Mr Meredith said.

“Once this sequence of events starts, these three females had to be killed.”

O’Dempsey, a 78-year-old Warwick resident, is also due to face trial next year.

Source: http://www.abc.net.au/news/2016-11-21/mcculkin-murders-gary-dubois-lawyers-query-witness-reliability/8042470