Criminal prosecutions in Minnesota’s most notorious financial fraud case came to a close Friday with the sentencing of the final three defendants involved in the $3.65 billion Ponzi scheme orchestrated by jailed former businessman Tom Petters.

The trio of sentencings brought to 126½ years the collective prison terms for the 13 who pleaded guilty or were convicted for their role in the Petters case, whose investigation and prosecution began just over five years ago.

However, there was a first Friday when former hedge fund account manager Michelle Palm became the only defendant in the Petters case to be placed on probation rather than receiving a prison term or home detention.

U.S. District Judge Richard Kyle said Palm’s assistance to the government in its investigation, her genuine remorse and lack of profiteering from the proceeds of the fraud mitigated the need to punish her with jail time.

“Miss Palm made a mistake,” Kyle said. “She appears to be the only one in the Petters scene who did not make a profit one way or another. She has her head on straight.”

But earlier Friday, two Florida-based hedge fund managers were sentenced to multiple-year prison terms for their roles in providing large sums of money to the Petters operation from investors in their funds.

Hedge fund manager Bruce Prevost was sentenced to 7½ years in prison as one of the key fundraisers in the Ponzi scheme, while his partner David Harrold received a five-year sentence.

Prevost and Harrold each pleaded guilty in 2011 to four counts of securities fraud for misleading investors about the specifics of their investment with the Petters operation from 2002 until 2008, when it collapsed.

Palm, a former hedge fund executive with Minnetonka-based Arrowhead Capital Management, had previously pleaded guilty to one count of securities fraud and one count of providing a false statement to the Securities and Exchange Commission, which she later corrected of her own volition.

“I should have told the truth from the beginning. I knew it was wrong. From then on, I have done everything that I could to make things right,” Palm told Kyle, with a courtroom of her friends and family looking on. “I’m ashamed of my mistakes. Assuming responsibility is another step to reclaiming my integrity and trust.”

Earlier in the day, an emotional and distraught Prevost apologized to his investors, family and friends in the St. Paul federal courtroom.

“I feel a crushing guilt inside,’’ Prevost said. “I wasn’t honest and I wasn’t fair to you [investors] and I am sorry for your pain and your loss.’’

Kyle said a substantial prison term was called for because “the amounts here that were lost are huge.’’

Prevost and Harrold lost approximately $720 million for clients by investing in the Petters fraud while collecting more than $58 million in fees and commissions.

Harrold’s comparatively short sentence was based on his “cooperation and substantial assistance’’ to government investigators, Kyle said at sentencing.

Addressing the judge, Harrold said: “I have no excuses for my wrongdoing. When I learned of the Petters Ponzi scheme, it ripped my heart open. It consumes my thoughts every day.’’

Both of the Florida residents were introduced to Petters by Frank Vennes Jr., a born-again ex-convict who served as the financial conduit between their Palm Beach Capital Management operation and Petters. Prevost and Harrold both said their Christian beliefs convinced them that Vennes was on the up-and-up.

Vennes, who is serving 15 years in prison for his role in the scheme, also served as the connection between Arrowhead and Petters. Arrowhead was run by James Fry, a Mound businessman who is serving a 17½-year prison sentence.

According to the charges against Prevost, Harrold and Palm, each was involved in a sales strategy that misled investors about the source of income from their investments. Instead of coming directly from big-box retailers for the sale of electronic goods as advertised, the investment returns were coming from bank accounts controlled by Petters, thus hiding the fact that no legitimate transactions of electronic goods took place.

The three also were charged with failing to inform investors when 90-day promissory notes began to run late and were on the verge of going into default.

After being charged in connection with the Ponzi scheme, all three became cooperating government witnesses. Palm testified at Fry’s trial.