A former Petaluma real estate agent charged with bilking dozens of investors in one of Sonoma County's largest Ponzi schemes will be sentenced to a maximum 20 years in prison if he admits the charges before trial, a judge said Monday.

Aldo Baccala, 73, is accused of swindling $20 million from 55 people who made loans for various projects including East Coast nursing homes, a Northern California mushroom farm and a Nevada car wash.

Prosecutors alleged Baccala used the money for other purposes and took new loans to pay back earlier investors. He was arrested in 2012 after he could no longer keep the scam afloat, prosecutors said.

He faces up to 160 years in prison if convicted at his March 28 trial of 135 counts of grand theft, securities fraud and elder financial abuse.

Judge Gary Medvigy announced he would limit Baccala's sentence to no more than 20 years if he pleaded guilty as charged. Medvigy cited Baccala's age and "blameless life" in extending the offer.

The judge declined to give a lower end for a possible sentence, saying he needed to hear first from victims and prosecutors.

Prosecutor Robin Hammond opposed the 20-year maximum, which could be completed in 10 years, saying she made a similar offer to Baccala at an earlier stage and he rejected it.

Now, she said her office along with the state Attorney General would seek 64 to 68 years. She asked for a quick decision because she was expending resources to prepare for trial, she said.

"It's the people's position that that (20-year sentence) doesn't address the loss that's occurred," Hammond said in court.

Medvigy ordered both sides to return Wednesday to see if Baccala will take the deal or go to trial.

The gray-haired man, who has been in custody since his arrest, seemed confused during parts of Monday's proceedings. Before the judge made his indication, Baccala asked in a soft voice if he would have time to consider a deal. Medvigy assured him he would.

Baccala raised millions of dollars for his investments, mostly by word of mouth, starting in the 1990s and continuing until he went bust in 2008.

Many retired people were drawn by the lure of double-digit returns. Some put up their homes and as much as $2 million in cash.

Baccala's debts mounted after he lost $8 million in the stock market over a five-year period starting in 2003. He sent letters to investors in 2008 saying he could no longer make promised monthly payments.

His assets were seized after the investors filed a civil lawsuit in 2009. It is unclear how much of a civil judgment has been paid to date.

You can reach Staff Writer Paul Payne at 568-5312 or paul.payne@pressdemocrat.com