Nearly five years ago, former Chicago Board of Trade chairman Patrick Arbor left the country and moved his assets overseas to avoid paying a court-ordered $18 million divorce judgment to his ex-wife.

On Monday, Arbor was arrested in Boston by Massachusetts State Police after he slipped into the country to attend his grandson’s graduation, only to be released again hours later when Cook County sheriff’s officials declined to extradite him.

Arbor, 81, was taken into custody at 1:05 p.m. at Boston College Alumni Stadium by officers serving an Illinois arrest warrant, said Massachusetts State Police spokesman Sgt. Paul Sullivan.

Sullivan said Massachusetts officials then informed Cook County of the arrest. But officials here did not want to bring him back to Chicago, Sullivan said.

At that point, Massachusetts police no longer had a valid reason to hold Arbor, he said.

Cara Smith, a spokeswoman for Sheriff Thomas Dart, said sheriff’s officials declined to pursue the matter after checking with Circuit Judge Myron Mackoff, who Smith said had issued the warrant.

Smith initially said the judge had advised the sheriff’s office that the warrant was not valid outside Illinois.

She later clarified that sheriff’s personnel made that determination on their own, in part because of confusion over who would pay the cost of returning Arbor.

Larry Byrne, one of the lawyers for Arbor’s ex-wife, Antoinette Vigilante, was not happy.

“I’m surprised the Cook County sheriff let that happen,” Byrne said. “We’re adding language to this order at their request that should prevent it from ever happening again.”

Arbor was arrested on a type of civil warrant known as a body attachment, which triggers different procedures than would a criminal arrest warrant, Smith said. Arbor faces no criminal charges.

Arbor has essentially been dodging the warrant for civil contempt of court since he fled the country around 2013 in the midst of his court fight with his then-wife Vigilante. The couple was married for 17 years.

Arbor appealed the judgment against him, but the Illinois Supreme Court declined to take the case.

Sources said Arbor flew into the U.S. last week from Switzerland.

In a 2016 deposition taken in a related case, Arbor testified he had become a resident of Frosinone, Italy.

But he also has been known to spend time in Mexico.

Lawyers for Vigilante have indicated in court filings that they believe Arbor surreptitiously returns to the U.S. on occasion.

If returned to Illinois, Arbor could be required to post a bond in the amount of the overdue maintenance payment due his ex-wife—about $300,000.

He also would have to allow his ex-wife’s attorneys to question him about the location of his assets. So far, Arbor has succeeded in keeping most of his holdings beyond their reach.

Arbor was once regarded as a major player in Chicago politics, in particular when he chaired the Board of Trade from 1993 to 1999.

In February, he was listed as co-chairman of a fundraiser for Cook County Board President Toni Preckwinkle, but did not attend.

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