When the FBI opened its investigation into former Fall River Mayor Jasiel Correia, it was focused on a tech company he founded before taking office called SnoOwl.

But prosecutors told a federal judge on Monday that when they met one of Correia’s investors, Tony Costa, they realized they were on the heels of one of Massachusetts’ biggest public corruption scandals in recent memory.

Costa, a local landlord and unlicensed marijuana dealer, later testified at Correia’s trial that he passed more than $70,000 in cash bribes directly into the mayor’s hands. The money came from a businessman seeking Correia’s approval to open a retail marijuana store in Fall River. Recreational sales of the drug had been legalized in Massachusetts only a few months earlier.

“It was frankly unfathomable to us that any corruption occurred after he was under investigation for SnoOwl,” said Zachary Hafer, the case’s lead prosecutor.

But Costa’s cooperation “opened the floodgates,” Hafer said, leading investigators to 10 other witnesses who described Correia’s crimes as mayor. A four-week trial ended this May with Correia’s conviction on 21 charges.

Correia was found innocent of soliciting a Rolex watch in exchange for connecting Costa’s building to the city’s water system free of charge. The verdict came after jurors raised questions about whether a gift Costa volunteered after the work was done counted as bribery.

Hafer argued at Costa’s sentencing hearing on Monday that he should be spared jail time.

“Without his cooperation, Correia’s rampant corruption would not have come to light,” Hafer wrote in a sentencing memo. At the time, “the government did not have anything resembling a chargeable corruption case, and it was running out of ways to make one,” Hafer wrote. 

Judge Douglas Woodlock ordered that Costa serve 15 months under house arrest and pay more than $150,000 to the government. Costa will also be subject to three years of probation, during which he’s required to volunteer at least 100 hours of community service each year.

The sentence allows Costa to continue working as a landlord and property manager while he supports an elderly mother and disabled sister, his lawyer Daniel Rabinovitz said. 

It also departs significantly from federal sentencing guidelines that recommended Costa serve eight to ten years in prison.

“Somebody like Mr. Costa understands that the first person in the door is the person who’s going to have the best treatment,” Woodlock said after announcing the sentence. “That’s part of saying to those who were involved in this sort of thing, ‘You do the right thing and you’re going to get a special benefit’ — a rather dramatic benefit in the case of Mr. Costa.”

Four other defendants are still waiting for their sentences, including Correia himself. The former mayor is expected to return to court in September.

Woodlock rejected a plea agreement earlier this month that would have spared jail time for Correia’s former campaign manager and chief of staff, Gen Andrade. 

Ben Berke is the South Coast Bureau Reporter for The Public’s Radio. He can be reached at bberke@thepublicsradio.org.