More than 130 suspected Nazi war criminals, SS guards and others who may have participated in atrocities during the second world war collected US$20.2m in retirement benefits, according to the US inspector general of social security.

In a report scheduled for public release next week and obtained by the Associated Press, the inspector general said nearly a quarter of the total, $5.7m, went to individuals who were found to have played a role in the Nazi persecution and had been deported. More than $14m was paid to people who were not deported but were alleged or found to have assisted the Nazis during a period in which millions of Jews perished in the Holocaust.

The report comes seven months after an AP investigation revealed benefits were paid to former Nazis after they were forced out of the United States. The Associated Press found that the justice department used a legal loophole to persuade Nazi suspects to leave the US in exchange for social security benefits. If they agreed to go voluntarily, or simply fled the country before being deported, they could keep their benefits.

Congress reacted swiftly by passing legislation to close the loophole and bar Nazi suspects from receiving benefits. President Barack Obama signed the measure into law late in 2014.

Congresswoman Carolyn Maloney, a New York Democrat, requested the inspector general look into the scope of the payments following the investigation.

“This report is another reminder that we must never forget the atrocities committed by the Nazis,” Maloney said. “According to this report 133 alleged and confirmed Nazis actively worked to conceal their true identities from our government and received millions of dollars in social security payments.”

The report does not include the names of the former Nazis and is narrowly focused on how many Nazi suspects received benefits. It criticizes the Social Security Administration for improperly paying four beneficiaries $15,658 because it did not suspend the benefits in time.

The report includes a detailed breakdown of how the payments were distributed.

The Social Security Administration in 2014 refused the AP’s request that it provide the total number of Nazi suspects who received benefits and the dollar amounts.