The 46-foot yacht, usually moored at Chicago’s Burnham Harbor, goes by the name Expelliarmus — a word Harry Potter exclaims when he wields his magic wand.

But, like magic, the pleasure craft with two bedrooms and two bathrooms seems to have disappeared — the latest mystery to emerge as federal agents investigate the failure of Bridgeport’s clout-heavy Washington Federal Bank for Savings 18 months ago, the hanging death of bank president John F. Gembara and millions of dollars in loans he gave his friend Robert Kowalski, a Chicago lawyer now charged with bankruptcy fraud.

Therese Gembara, the bank president’s widow, has told the courts the yacht’s part of his estate.

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Kowalski’s estranged wife Martha Padilla says the boat is a marital asset that’s part of their long-running divorce case.

And Kowalski claims the boat as one of the assets in the bankruptcy petition he filed as federal regulators sought to collect as much as $27 million in loans they say he owed Gembara’s bank.

Now, federal regulators have signaled they might try to seize the boat to help pay off Kowalski’s debt to the bank, though they aren’t sure what Expelliarmus is worth.

There’s one big problem, though: No one seems to know where the yacht is — or, at least, they aren’t saying.

Therese Gembara “has no knowledge as to the location of the boat and believes it was confiscated after [her husband’s] death by either the FBI or the FDIC,” according to a filing with an inventory of her husband’s estate her lawyer gave a Cook County judge in April.

A lawyer for the FDIC says federal regulators haven’t seized the boat.

Investigators for other federal agencies won’t talk about much of anything surrounding the failed Bridgeport bank.

Not the bank’s December 2017 failure — which had been the most-recent in the United States until Enloe State Bank in Cooper, Texas, was shut down May 31.

Not how Gembara was found hanged in what was deemed by police and the Cook County medical examiner a suicide at the Park Ridge home of a bank customer records show had millions of dollars in loans from his bank.

And not the whereabouts of the boat Gembara bought with Robert Kowalski and his brother William Kowalski.

Government officials believe Kowalski knows where the yacht is and that one of Kowalski’s business partners and law clients might have possession of it. The man told the Chicago Sun-Times he doesn’t have the vessel.

Kowalski, 57, couldn’t be reached. He and his sister Jan Kowalski, both attorneys, were jailed in March for contempt of court related to the disappearance of $250,000 in cash, as a U.S. bankruptcy judge tried to get an accounting of Kowalski’s assets, now being liquidated to settle his debts.

The Kowalskis were released a few days ago. But a Cook County divorce court judge then ordered Robert Kowalski — a smalltime developer who calls himself “Bob the Builder” — to be held at the Cook County Jail for failing to pay child support.

Kowalski’s estranged wife has asked a divorce court judge to order Kowalski to give her and their children “access” to the boat.

Kowalski has told bankruptcy court officials he lived on the boat last summer, when it was docked in Burnham Harbor near Soldier Field.

Kowalski estimated the value of the fiberglass-hulled Sea Ray Sundancer 460 at $180,000, according to the bankruptcy petition he filed in March 2018. He reported that Huntington National Bank has a lien against the vessel for $171,849.

Gembara and the Kowalski brothers bought the boat on July 11, 2007, according to Illinois Department of Natural Resources records. They were the third owners of the 2004 watercraft. State records show all three men had an ownership stake when they last renewed the registration, which was three years ago. The documents don’t say how much they paid for the vessel.

As part of a lawsuit William Kowalski filed in DuPage County five years ago to end their business relationship, he transferred his stake in the boat to his brother, records show. Their business had involved buying houses, financing the purchases with loans from Gembara’s bank and leasing them to tenants with Section 8 housing vouchers under which the federal government subsidized their rent payments.

Gembara, who lived in Palos Hills, was 56 when he was found dead on Dec. 3, 2017 — seated in a chair, a rope around his neck — inside the Park Ridge home of Marek Matczuk, the Sun-Times has reported.

Matczuk, 56, is a building contractor and friend of Robert Kowalski who owed Gembara’s bank nearly $2 million, records show, including a mortgage on the home.

The Park Ridge police and the medical examiner decided Gembara killed himself.

A lawyer for the banker’s widow has said some family members don’t believe he committed suicide; they think somebody killed him. Kowalski also has told the Sun-Times he thinks Gembara was murdered.

A dozen days after Gembara was found dead, federal regulators shut down the bank that he headed and his grandfather founded more than a century ago.

Federal auditors later determined that Gembara was involved in an $82.6 million fraud scheme — losses that likely will be covered by a federal insurance fund if the government can’t recover the money from borrowers including Kowalski.

Kowalski has said he had repaid the loans but that Gembara didn’t document his repayments.

Another mystery involving Kowalski recently was solved: Federal authorities located and opened a 4- to 5-feet-tall safe they’d said was missing from Kowalski’s law office, sources told the Sun-Times. But authorities won’t say what was inside.