For Worcester Polytechnic Institute, it was a singular embarrassment when it emerged last month that a post-divorce lawsuit featuring the school’s top benefactor contained claims by his ex-wife that his charitable gifts included money he illegally hid from her.

But that ugly story has taken a turn toward the bizarre.

A review of court cases in three states reveals significantly more: a dysfunctional wealthy family engaged in a venomous fight in which retired businessman and WPI donor Robert Foisie is accused by family members of having hired a hit man to kill one of his two adult children.

Foisie, 82, offered a former East Boston man a $20,000 down payment to murder his son or find someone else to do the job, according to allegations in a legal petition by his children that reached Nevada’s highest court. Foisie did so, legal filings allege, because he was angry that his son and daughter removed him as manager of a family investment company.

The children and their mother have made other dramatic allegations about Foisie, a West Hartford native, in multiple lawsuits in Massachusetts, Connecticut, and Nevada. Among them: He’s being investigated by the FBI for wire fraud, he’s negotiating with the IRS over tax evasion, and he stashed tens of millions of dollars abroad to prevent his ex-wife from getting the money.

Foisie has aggressively fought the suits and emerged largely victorious in at least one of them. The sensational claim about a murder plot was barred by a judge from being considered in court.

The family legal fracas poses a public relations challenge for WPI, which has emblazoned Foisie’s name across campus. Its business school is named after him, as is a scholarship program, and a $49 million building called the Foisie Innovation Studio is under construction. A 1956 graduate, he is the university’s single largest patron, having donated $63 million to WPI over his lifetime.

After inquiries from the Globe, WPI issued a statement Thursday calling the allegations “concerning’’ and saying that “we are following this closely, and will take action as warranted.’’

Then, on Friday, WPI president Laurie Leshin issued a public letter to the campus community that reads, in part: “Upcoming news reports may focus on personal disputes involving the Foisie family. . . . We don’t know whether any of the allegations are true or false, but I want to assure you that we are taking the situation seriously. While other universities and nonprofits have faced issues related to donors or major gifts, this is new territory for WPI. We are following this closely and will take action, if necessary, to ensure that we are aligned with best practices.’’

The letter added that the Foisie Innovation Studio “is on track and will remain so,’’ noting that Robert Foisie is not the only donor to the project and “full funding to complete construction is in place.’’

The Foisie family did not return calls from the Globe, and their lawyers declined to comment due to “ongoing litigation,’’ said Adam S. Mocciolo, a Bridgeport, Conn., attorney representing Foisie’s ex-wife, Janet.

In legal documents filed in September in the Supreme Court of Nevada, where the family’s investment company is based, Robert Foisie’s children — Michael Foisie, 55, of New Hampshire, and Lauren “Dolly’’ Foisie Glennon, 53, of Connecticut — describe the alleged murder plot. According to those documents, Michael Foisie notified the FBI and “has been in fear for his own life since learning of the allegations.’’

An FBI spokeswoman said the agency cannot confirm or deny the existence of an investigation.

Contacted by the Globe, Jeffrey P. Luszeck, a Las Vegas attorney representing Robert Foisie in the Nevada case, said, “I don’t think I’m at liberty to answer your questions.’’

The allegations against Foisie are unproven, and a Nevada jury decided in his favor on several points in December. In that case, the Nevada Supreme Court affirmed a lower court’s decision to refuse to allow the murder plot allegations to be entered as evidence.

Legal filings say Robert Foisie has denied his family’s allegations and also say “he is merely a generous benefactor who wants to assist children.’’

After graduating from WPI and Cornell University, Robert Foisie worked as an engineer and later became president of Hartford-based Matik Inc., a distributor for European manufacturers, and owned a Swiss packaging company. More recently, he has invested in golf and ski resorts in Vermont, including Haystack Mountain in Wilmington, a venture in which he lost $18 million, according to divorce documents.

The root of the family dispute appears to have been the decision by Foisie’s children in May 2015 to remove him as a manager of an investment company in Nevada worth at least $50 million, an action he calls “a conspiracy.’’

It is unclear why his children moved against him, although their legal filings claim that “Robert was going to steal money and move to the Cayman Islands,’’ a charge he described in his court responses as “knowingly false and fraudulent.’’

In retaliation for his removal, Robert Foisie, his family alleges, tried to foreclose on a condominium complex Michael was involved in building in Norwich, Conn., damaging the property’s value.

In another alleged retaliatory measure, Robert Foisie asked James Balzotti, a Florida man who grew up in East Boston, to murder Michael, even giving him “written instructions’’ detailing where Michael could be found.

After Balzotti told his former business partner, Robert Casale, also of Florida, about Foisie’s attempt to hire him as a “hit man,’’ Casale notified the Foisie family because he “felt a moral obligation’’ to do so, legal filings say.

Reached by telephone, Balzotti declined to comment on the record. His attorney, Timothy J. Goulden of Nashua, did not return a call.

Casale also declined to comment on the record when reached by phone, saying, “I won’t add any more than what’s in the litigation.’’

Robert and Janet Foisie, who is 81 and lives in Long Boat Key, Fla., divorced in 2011 after 50 years of marriage.

Contacted by the Globe, a friend of Janet, Lucy Malis, 65, of Port Saint Lucie, Fla., said she connected Casale to Janet after he said he had information concerning “the safety of her family.’’

“They’re just doing what they have to do,’’ Malis said of Janet, Michael, and Lauren Foisie. “It’s been very hard on them, and it seems like it’s never-ending, but they’re a very strong family, Janet especially.’’

In her lawsuit against WPI, Janet Foisie claims that all of Robert Foisie’s $40 million donation to the school in 2014 — WPI’s largest gift ever — may have come from secret overseas accounts, including some in Switzerland, that should have been disclosed during their divorce negotiations.

She also says he may be continuing to donate money that had been hidden from her, noting that the government of the Caribbean island of Antigua announced in December that Robert Foisie would fund “an unlimited number of scholarships’’ for undergraduate engineering students from Antigua and neighboring Barbuda to attend WPI.

Janet Foisie has asked a court to prevent the school from spending his donations until her case is resolved.

Robert Foisie lives in Florida, where he owns The Legacy, a private golf and tennis club in Port St. Lucie, but several of his acquaintances told the Globe he may now be residing in Antigua.

“This is such a conundrum’’ for WPI, said Alan Cantor, a New Hampshire consultant to nonprofits. “You really can’t expect the development offices of a nonprofit to know these things, so I presume the school is an innocent bystander.’’

Sacha Pfeiffer can be reached at pfeiffer@globe.com. Follow her on Twitter at @SachaPfeiffer.