CONVICTED triple murderer Max Sica has been acquitted of molesting a girl, aged nine to 13, over four years.
Sica, who is already serving a minimum 35-year jail sentence, was granted a judge-only trial after his lengthy murder trial last year attracted extensive media coverage.
Judge Michael Shanahan, in a 50-page written judgment handed down on Friday, said the girl impressed him as a witness but he also had to look at the objective evidence before him.
"The case for the prosecution depends on the assessment of the (girl's) credibility," he said.
"There is no independent evidence that supports her allegations with respect to any of the alleged offences."
Judge Shanahan said the medical evidence caused him "significant concern".
He said the girl's sexual anatomy indicated she had never had sex but she had claimed they had sex more than 100 times.
"On the (girl's) account there was regular penetration of her vagina to an extent and in circumstances that would be thought to have damaged her hymen," he said.
"Considering the medical evidence I can not be satisfied beyond a reasonable doubt that the penetrative acts occurred as described by the (girl), particularly in relation to their frequency."
Judge Shanahan said this brought the girl's credibility into question and therefore reasonable doubt about the Sica's guilt.
He acquitted Sica on all 21 counts, including maintaining a sexual relationship with a child and rape.
The allegations came to light after the girl told her school friends about having a sexual relationship with an older man in 2008.
Sica received three life sentences last year for brutally murdering Singh siblings Neelma, 24, Kunal, 18, and Sidhi, 12, in their Brisbane home in 2003.
Sica will appeal those guilty verdicts in the Court of Appeal in May.
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