HALIFAX -- A federal lawyer says a Nova Scotia man has failed to prove he was wrongfully convicted of statutory rape in 1970 as the result of a negligent investigation by the RCMP.

Angela Green told the Nova Scotia Supreme Court on Thursday that Gerald Barton's lawyer failed to present any evidence that the lead investigator in the case failed to meet a common sense standard of care.

In her closing argument, Green said there was no evidence to suggest Earl Hamilton -- a corporal at the time in Digby who retired as an inspector -- was careless in his work or that he fabricated an incriminating statement attributed to Barton, who was 19 at the time.

Barton is claiming he never gave an incriminating statement to police about the crime of having sex with a female between the ages of 14 and 16.

Before Green began her argument, Barton's lawyer told the court his client was withdrawing his claim of malicious prosecution against the provincial attorney general but the case would continue against the RCMP for negligent investigation.

Dale Dunlop said it's clear that the Crown attorney in the case could only act on the statements given to him by the RCMP.

On Wednesday, former Crown attorney Charles Haliburton testified that Barton had pleaded guilty to the charge just as his trial was about to begin on Jan. 14, 1970.

Barton, now 64, maintains he did not plead guilty.

Haliburton, a retired provincial Supreme Court judge, cited documents he retrieved from an old storage room in Digby, saying he had written the following note on one of them: "Guilty plea on trial."

Aside from the notation on his file and documents from a preliminary hearing, Haliburton said there is no record of the court proceedings that led to Barton's conviction.

He said a large cache of records were destroyed about 15 years ago when records at the Digby County courthouse were moved to Halifax.

Dunlop asked Haliburton why he decided to charge Barton with having sex with a minor, even though the complainant's statement to police indicated that she had been violently raped, an assertion Haliburton did not dispute.

"It was the one (charge) that had a real prospect of conviction," Haliburton said. "It's the one that (Barton) admitted to" in his statement to police.

Earlier in the trial, Barton told the court that the statement attributed to him was a fabrication. In it, Barton is quoted as saying he had consensual sex with a 14-year-old girl at her home in Jordantown in 1969, but he testified Monday that he never spoke to any officers.

Court records show Barton spent a few hours in jail and was sentenced to one year of probation.

In January 2011, the Nova Scotia Court of Appeal admitted DNA evidence that proved Barton was not the father of the child born to the original complainant, who told police in 2008 she had lied about Barton.

The genetic tests said the brother of Barton's accuser was the father of the child. The brother was later charged with indecent assault, but the charge was dismissed in 2009. His name and that of his siblings and immediate family are protected by a publication ban.