GREENWICH, Conn., Sept. 23 - Even in Greenwich, the $15 million to $18 million fortune they stand to inherit stands out as serious money. And yet few would trade places with them. They are 11-, 8- and 5-year-old siblings who have endured nearly as much tragedy in their short lives as the waifs of the Lemony Snicket stories who lurch from crisis to crisis.

Last month, their mother was convicted of killing their father in 2003 at their luxurious Hong Kong home, after he learned of her affair with a television repairman. Their maternal grandfather moved them to Illinois to live with him but changed his mind after two weeks.

Then the rich uncle who gave them refuge at his picture-perfect home in Greenwich was charged with orchestrating a fraud that is punishable by years in prison and could leave him penniless. His wife, the person primarily in charge of taking care of the children in the last year and a half, is seeking a divorce. She has said she would like to keep custody, but must battle creditors to preserve any semblance of the life she has led.

The question, then, of who will raise the three Kissel children, and, not coincidentally, what happens to the money their father left behind, will now be left to the American judicial system. Stamford Superior Court has begun revisiting the issue of temporary custody, and Surrogate's Court in Manhattan, which probated their father's will, is scheduled to take up the larger question of guardianship next Friday.

In the meantime, the squabbling continues, extending a spectacle that began overseas in late 2003 when Nancy Ann Kissel was accused of giving her husband, Robert P. Kissel, a Merrill Lynch executive, a sedative-laced milkshake before clubbing him to death. It spread here with this summer's news that Robert's brother, Andrew M. Kissel, had criminal and marital problems of his own.

Squaring off over custody and guardianship of the children are Andrew's estranged wife, Hayley Wolff Kissel, a former stock analyst on Wall Street, and his sister, Jane Kissel Clayton of Mercer Island, Wash.

Ms. Clayton has criticized the children's current living arrangement as "bleak and problematic" and accused her sister-in-law in court of using the children as pawns to solve her own deepening financial woes.

Court records show that the Kissels of Greenwich received $170,000 from Robert P. Kissel's estate last year and are operating under an agreement in which the estate allots $8,000 a month toward the children's food, clothing, travel, sports, gifts and baby sitter, an amount that can rise or fall on the basis of actual expenses. Major outlays like tuition and medical bills are not expected to come from that but are paid directly by the estate.

"Hayley has represented to me that her and Andrew's legal problems have left her in a desperate financial situation and that she intends to fight for custody of Robbie's children - even though she admits that it is not in their best interests to remain with her - in order to benefit from their considerable assets," Ms. Clayton wrote in an affidavit.

Though Hayley Kissel petitioned for divorce earlier this year and is now embroiled in civil litigation stemming from Andrew's ill-fated deals, she seems prepared to do battle over the three children, Elaine, June and Reis, as well.

She notified Stamford Superior Court last month that she was interested in remaining responsible for the children despite her own changed circumstances. Without disclosing much detail about the tumult in her life, she wrote, "I take my role as custodian very seriously, care deeply for the welfare of the Kissel children and am happy to continue as temporary custodian."

Lawyers and family members say they believe she is the author of an item posted on the Web earlier this month by an author identified only as H who described seeing to it that her three young charges had the same fun-filled year as her two children: a year packed with sleepovers with friends, music lessons and weekend ski trips. Although it is "far from a perfect situation," the writer wrote, "they are doing well, all things considered."

"They wake up to a full breakfast (cooked not by a maid), lunches for five are packed in the morning and we sit down to a family dinner almost every night," the writer continued.

The elder niece, according to the posting, went to sleepaway camp this summer, as has been her custom, and the younger two children "swam in fresh mountain springs, jumped off rocks into beautiful lakes, learned how to knit (sort of), made macramé necklaces and went blazing down the Alpine Slide."

Asked about the latest developments, Hayley Kissel's lawyer, Joseph W. Martini, said neither he nor his client would have any further comment.

In an interview, William J. Kissel, the children's paternal grandfather, said that he found the Web posting inappropriate and that he supported his daughter's application for custody and guardianship, citing many of the assertions in Jane Clayton's filings that question Hayley Kissel's motives. "Better now than later," he said.

"Andrew is in deep trouble," he said, "and it wouldn't be appropriate to have the children in a house without a mother and a father, where the wife needs the children to support her lifestyle."

In her court filings, Ms. Clayton has said that trouble arose in Andrew and Hayley's marriage in July 2004, when Hayley Kissel learned that her husband was having an affair. Ms. Clayton recounted conversations from that period that left her "deeply worried," in which her sister-in-law told her that Andrew's business was a "Ponzi scheme" and that one of the reasons they moved to Connecticut was that he "stole money from their New York City condo" when they lived in Manhattan.

Though the couple later reconciled, Ms. Clayton stated that she remained concerned about the children's welfare. Those concerns, she wrote, flared anew in the winter, when her sister-in-law resolved to get a divorce and left town without waiting for her elder niece to return from a school trip. Ultimately, a family friend picked the girl up, according to Ms. Clayton.

Ms. Clayton said in court filings that her sister-in-law made it clear at that time she did not need the "extra stress" of the additional children, and the two agreed that the children would remain in Connecticut through the school year, and then join Ms. Clayton and her husband, Richard, an executive at Microsoft.

Pressing personal problems are now causing her sister-in-law to renege, Ms. Clayton said. "Hayley told me that Andrew had leveraged everything, including their house in Vermont, and that he had left her with nothing," she wrote.

Citing a conversation she said they had on July 7, Ms. Clayton quoted her sister-in-law as saying: "I am going to do what is best for myself. If I keep the children, it may not be the best thing for them, but at least I won't be out on the street. I have nothing left."

Ms. Clayton's lawyer, Randy M. Mastro of Gibson Dunn & Crutcher, said in an interview that his client's recollections were based on contemporaneous notes she took of conversations she had with her sister-in-law.

An item in the probate court's files suggests one reason it may be hard to leave the children where they are: the possibility that the estate may have to join a lawsuit against Andrew M. Kissel.

Back in June, Ms. Clayton, a co-executor of her brother's estate, testified during the murder trial that the estate was worth $18 million. That estimate has now been lowered to $15.5 million. Some of that gap can be attributed to investments that Robert Kissel had made in apartment buildings in New Jersey, which Andrew Kissel is now accused of having secretly sold out from under his own partners. That money may now be hard to recover, according to Mr. Mastro.