South Australia Police and Australian Federal Police are using ground penetrating radar in a hope to uncover clues relating to the unsolved disappearance of 10-year-old girl Louise Bell.

Police are hoping to use the new forensic methods to reveal evidence in the unsolved case, determined to be a murder by police, after the girl was taken from her bedroom at Holly Rise in Hackham West in January of 1983.

Officer in charge of the SAPOL Major Crime Branch, Detective Superintendent Grant Moyle told 891 Breakfast detective had previously excavated the property yard in 1991, and after recent review believed further investigations were required.

"We're satisfied that there was still further things to be done and certainly with the advance of technology and science that we were able to more thoroughly examine that backyard."

D Supt Moyle said the new equipment provided by the Australian Federal Police was able to detect density abnormalities caused by the likes of soil movement or the digging of holes.

He said police had previously excavated a section of the backyard, but new investigations were focussing on different areas of the property.

"For completeness sake that just has to be done properly ... to hopefully unravel some more evidence and bring some closure for the family."

The body of Louise Bell was never found.

Detectives have briefed Louise's father on the continuing of investigations.

"It's very distressing for him and his wife and family.

"We don't do these thing lightly because we are very aware the distress it causes the family," he said.

"We have done considerable research and spoken to a number of other people before we have got to this point in time."

An officer who was originally involved in the 1983 investigations has been brought out of retirement to help detectives go through previously submitted evidence.

Investigations will continue at the site for most of the week.

The history of the disappearance of Louise Bell

D Supt Moyle said Louise was believed to have been taken from her bedroom on 4 January 1983, with police finding the insect screen on her room's window had been tampered with.

"A short time after she was taken, a telephone call was made to a nearby resident by a person claiming to be involved in her abduction."

Ear rings belonging to Louise were found nearby, on the corner of South Road and Beach Road, with a pyjama top left on front yard of a neighbour's house some days later.

The mystery of Louise's disappearance was never solved, with police hoping to provide some answers for her family.

"At the end of the day they want Louise back and we're doing the best we can to try to achieve that."

Anyone with information they believe may be helpful to police investigations can contact Crime Stoppers on 1800 333 000.