Two Adelaide men have been sentenced to lengthy prison terms after orchestrating a fraudulent property investment scheme that stripped millions of dollars from vulnerable victims, many of whom had entrusted the men with their retirement savings.

In the South Australian District Court, Andre Langos, 44, of Fullarton, and Sam Smith, 58, of Brighton, were jailed for deceiving five investors into handing over more than $6 million between April 2019 and July 2020. Four of the victims were aged over 60.

During sentencing, Judge Anne Barnett described the offending as an exploitation of trust that had caused "far-reaching and life-changing impacts" on those affected.

The court heard that victims believed their money was being invested in legitimate property opportunities. Instead, the scheme unravelled, leaving participants financially devastated.

One victim described the experience as an "abhorrent betrayal", while another said it felt like "seeing your life burn down while already standing in the ruins and knowing someone else lit the match."

Judge Barnett noted that most of the victims were older and vulnerable individuals who had spent decades building their financial security.

"The financial and emotional consequences of your conduct have been profound," she told the offenders.

The court was told that Sam Smith had introduced several long-time acquaintances to Langos after previously investing with him. Some victims had known Smith for many years and trusted his recommendations.

After investors began questioning why their funds had not been returned, the pair allegedly reassured them that the money remained secure. Victims were then encouraged to contribute additional thousands of dollars, supposedly to facilitate the release of their investments.

The scheme eventually collapsed after victims sought legal advice and reported the matter to police.

Court documents revealed that the victims transferred a total of $6,043,000. Despite the enormous losses, only $40,000 had been repaid to one victim, and that payment related partly to a separate debt. The remaining victims have received nothing.

Langos pleaded guilty to 14 counts of aggravated deception and one count of deception, admitting responsibility for approximately $893,000 obtained through the scheme.

Smith pleaded guilty to six counts of aggravated deception and one count of deception, accepting responsibility for approximately $1.768 million.

Although the court acknowledged that both men had expressed remorse and possessed reasonable prospects for rehabilitation, Judge Barnett determined that immediate imprisonment was necessary given the seriousness of the offending.

Sam Smith was sentenced to seven years in prison, with a non-parole period of four years and nine months. He will be eligible to apply for parole in March 2031.

Andre Langos received a sentence of eight years' imprisonment, with a non-parole period of five years and six months, making him eligible to seek parole in December 2031.

The judge declined to order compensation, meaning victims may continue facing significant financial hardship without reimbursement.

The case has highlighted the devastating impact that investment fraud can have, particularly on older Australians who rely on savings accumulated over a lifetime of work.

For the victims, the emotional scars extend beyond the financial losses. Many described losing not only their retirement funds but also their confidence, independence and trust in others.

The sentencing brings a measure of accountability, but for those affected, the consequences of the deception are likely to endure for years to come.