Dieter Pfennig has been found guilty of the 1983 murder of Adelaide schoolgirl Louise Bell.

Supreme Court Justice Michael David delivered his verdict on Friday, urging the 68-year-old to reveal the location of the girl’s body.

Louise was abducted through her bedroom window in Hackham West in January 1983. The 10-year-old’s body has never been found.

Her disappearance sparked a police search of unprecedented scale in suburban Adelaide and it remained one of South Australia’s most enduring cold cases.

Pfennig was charged in 2013 after DNA scientists in the Netherlands linked him to Louise’s pyjama top, which was found after her death.

Justice David urged Pfennig to reveal the location of Louise’s body so her family and authorities could have closure.

“That may or may not affect my sentencing,” he told the court in Adelaide as Pfennig stood in the dock.

‘”But I want to bring this whole ghastly thing to an end.”

Pfennig, a former maths and science teacher, did not give evidence at his trial, which ran for several months over 2015 and 2016.

Court sketch of Dieter Pfennig, accused of the murder of schoolgirl Louise Bell.

During the trial, prosecutor Sandi McDonald said the chances of a random male providing such a DNA match were greater than one in one billion.

But defence lawyer Paul Charman argued the evidence fell short of proving Pfennig committed the crime.

He said the DNA could have ended up on the top through contact with Pfennig’s daughter, who played basketball with Louise.

The pyjama top was found, neatly folded, on a neighbour’s front lawn, the trial heard.

The woman who discovered it also received a phone call from a man who said Louise was with him. The voice told her to look under a broken brick at a nearby corner, where police found the girl’s earrings.

The court heard Pfennig suffered from insomnia and liked to walk the streets at night. He lived in the same neighbourhood as Louise when she went missing.

The South Adelaide house where Louise Bell was allegedly taken by Dieter Pfennig through a window.

Prosecutors said Pfennig admitted killing the girl to his fellow inmates on two separate occasions while he was in jail for another child murder.

He was convicted of killing 10-year-old Michael Black in 1989 and he was in jail when he was arrested over Louise’s murder.

The trial paused when Pfennig suffered a heart attack in Yatala Prison in March. He was resuscitated and required surgery before returning to court three weeks later.

Another man, Raymond Geesing, was originally sentenced to life in prison for Louise’s murder but that decision was quashed on appeal in 1985.

In 1991, police searched a home that used to belong to Pfennig, pulling up floorboards and excavating part of the back yard.

They returned to the home in 2012 and excavated other areas after using ground-penetrating radar.

Witnesses at the trial included Pfennig’s daughter, a librarian, a student, police officers and forensic specialists.

Pfennig will return to court in December for sentencing submissions.