Holdem has completed intensive group and individual treatment while in prison, but the Board noted he'd "demonstrated little treatment gain".
He is still considered a high risk for both violent and sexual offending.
A psychologist who gave evidence to the Board said that Holdem reported having a lack of sexual interest, but said that his self-reporting could not be considered reliable.
"Even if Mr Holdem's rehabilitation work is completed it is likely that following the lengthy period of time he has spent in prison reintegrative activities will be crucial," the Board decision said.
"In our view even on the most optimistic scenario Mr Holdem has a significant degree of work to complete before he would be suitable for release.
"We note in this regard that the psychologist describes Mr Holdem's rehabilitative needs as 'immense'."
When he killed Louisa, Holdem had just been released from prison for the abduction and attempted murder of a 10-year-old girl.
His rap sheet includes an attempted rape in 1982, and multiple instances of committing indecencies on a child.
