Victorian Supreme Court Justice Elizabeth Curtain said the killing was a ‘‘serious and grave’’ example of the crime of murder.

‘‘You were involved with others in the abduction of a defenceless 13-year-old girl from the sanctuary of her home in circumstances that must’ve been terrifying for her,’’ Justice Curtain told Camilleri on Thursday.

‘‘Your conduct bespeaks criminality of a very high order and is demonstrative of a cruel and callous regard for the sanctity of human life.

‘‘You present as a real and serious danger to the community, particularly young girls.’’

Camilleri is already serving two life sentences without the prospect of parole for the murders of Bega schoolgirls Lauren Barry and Nichole Collins in 1997.

Justice Curtain said she was satisfied Camilleri acted with one or two other men in abducting Prue from her Glenroy home and murdering her in February 1992.

Prue’s mother, Jenny Bird, said she was pleased with Justice Curtain’s conclusion that Camilleri did not act alone.

‘‘I haven’t been satisfied from the day I reported Prue missing with the police, I’m still not satisfied today, but this was the best I was hoping for – that it was ruled that he didn’t act alone,’’ she said outside court.

Ms Bird said she had not given up hope that Justice Curtain’s determination that others were involved could one day see the investigation reopened.

Prue’s body has never been found. Camilleri, 43, confessed last December to murdering Prue.