The man convicted of murder in the death of Winnipeg schoolgirl Candace Derksen won't be eligible for parole for 25 years, Manitoba Chief Justice Glenn Joyal ruled Thursday.

Mark Edward Grant, 47, was found guilty of second-degree murder by a Queen's Bench jury on Feb. 18, following a five-week trial that focused on DNA evidence.

He had faced a first-degree murder charge but the seven-man, five-woman jury found him not guilty in favour of convicting him of the lesser offence.

A second-degree murder conviction carries with it no chance of parole for a minimum of 10 years, but it is within the judge's discretion to raise it as high as 25 years, which Joyal decided to do.

Crown prosecutor Brian Bell had argued for the maximum term, noting in court on Thursday that Grant had spent nearly half his life behind bars for other crimes and showed no improvement, despite years of treatment.

He said Grant's actions against Derksen were sadistic and he should spend the maximum amount of time behind bars.

Derksen, 13, was on her way home from school in November 1984 when she disappeared.

derksen-shed

The supply shed near the Nairn Overpass where Candace Derksen's frozen body was found. ((CBC))

Her frozen body was found six weeks later, on Jan. 13, 1985, on the dirt floor of a rarely used supply shed in a brickyard about 500 metres from her family's East Kildonan home.

Her arms and legs were bound with rope and she was partially wrapped in blankets.

Three pubic hairs were found on or near her body, although police said she had not been sexually assaulted.

Four scalp hairs were also found but police weren't able to test them for DNA until technology improved in 1993.

Even then the technology was not good enough to determine a DNA profile, and Derksen's death remained a mystery until 2006, when police learned a lab in Thunder Bay had the ability to run more extensive hair-shaft DNA tests.

In May 2007 police came forward with new forensic evidence linking Grant with the murder scene.