A judge Tuesday tossed out 17 felony charges against a Petaluma real estate agent accused of swindling investors out of $20 million, citing the co-mingling of funds as a barrier to proving the allegations.

But Judge Shelly Averill said there was sufficient evidence to place Aldo Baccala on trial for 135 counts including grand theft, securities fraud and elder financial abuse in an alleged Ponzi scheme that targeted many retired people.

The judge said the remaining 12 charges listed in the original 164-count complaint will be dismissed because prosecutors have decided not to proceed on them.

Averill noted the changes will not make a difference in the amount of prison time Baccala could get if convicted at trial. Baccala, 72, could spend the rest of his life behind bars, with enhancements for white-collar crime and other offenses.

"I think he should serve a lot of time for what he did to these poor people," said Wayne Seden of Santa Rosa, a retired engineer who says he lost $50,000 to Baccala. "He basically just stole from them."

Averill's ruling followed weeks of testimony from investigators and alleged victims of what is believed to be one of the largest Ponzi schemes in Sonoma County history.

Baccala is accused of luring 55 investors to his various holdings on promises of double-digit returns. Instead of plugging the money into the properties, he used it to make interest payments to other investors, prosecutors said.

Some investors, who put up as much as $2 million, lost their life savings, prosecutors said.

Baccala was arrested a year ago and has been in jail ever since. His bail is $2 million.

Averill ordered him to return to court June 12 for an arraignment on the charges.

Like many of the alleged victims, Seden said he was introduced to Baccala in 2005 by a friend. Seden invested an initial $50,000 in a Nevada car wash, getting a 12 percent annual return, he said.

When his money was all paid back, he decided to roll the investment into another Baccala offering — a nursing home in the southeastern United States, he said.

It fell apart in 2008 when Baccala suspended monthly interest payments, Seden said.

He was among a group of investors who launched a civil suit, winning a $21 million judgment. He has since received a portion of his money back, but not all of it, he said.

Seden said he was fortunate in that he didn't invest more. Some investors lost everything they had and were persuaded by Baccala to refinance their homes and hand over money, he said.

"He had no conscience," said Seden, who testified at the preliminary hearing.

District Attorney Jill Ravitch said the judge's ruling was consistent with the evidence. She said the case involved many senior citizens who knew Baccala and placed their trust in him.

"People who commit white-collar crimes are potentially subjected to imprisonment just like people who commit violent assaults," Ravitch said. "In some ways the crimes are more insidious because people lose their homes and their safety nets."

The District Attorney's Office has posted information for investors on its website at http://da.sonoma-county.org/content.aspx?sid=1023&id=2531