Friends and acquaintances of one of New York’s most prominent plaintiff’s lawyers, Melvyn Weiss, are pleading for leniency as a federal judge in Los Angeles prepares to sentence the former class-action king today on charges that he conspired to cover up secret payments his firm made to investors who helped bring securities lawsuits.

However, a new study could undercut those pleas by claiming that the scheme Weiss ran at his former firm, now known simply as Milberg LLP, inflated the legal fees in the cases involved and was not a victimless crime, as some of the veteran lawyer’s allies have argued.

In a plea deal with prosecutors, Weiss, 72, has agreed to accept a sentence of between 18 and 33 months of jail time. The government is pressing for 33 months. In court papers, Weiss’s lawyers argue for 18 months, half of which would be spent in home confinement or some nonprison setting.

READ THE LETTERS: Stanely Sporkin | Burt Neuborne | Thomas Suozzi | Richard Revesz | John Sexton | Fernando Maurette | Melvyn Weiss | Abraham Foxman.

The new research paper, conducted by a law professor at St. John’s University in Queens, Michael Perino, and published last week by a conservative think tank, the American Enterprise Institute, found that the fees awarded to Weiss’s law firm were higher in cases where prosecutors charged illegal payments were made. On average, the firm took 30% of the funds won in cases contained in the indictment versus 27% in cases where no illegal payments by the lawyers were alleged.

While the difference may seem small, it could be substantial in dollar terms given that Milberg brought in $251 million in fees in the cases which led to the charges. The study suggests that the need to pay a “kickback,” which often amounted to 10% of the fees earned in the case, prompted the firm to inflate its bills.

“I feel very strongly that the study is deeply flawed,” a lawyer for Weiss, Benjamin Brafman, told The New York Sun in an e-mail yesterday. “Not even the government has ever contended that shareholders suffered any loss. Not has anyone ever even suggested that the work of the firm was anything less than superb.” The defense lawyer said he felt it was inappropriate to elaborate in advance of today’s court proceeding.

While Mr. Perino’s study is not formally before Judge John Walter, who will impose the sentence this morning, Weiss’s lawyers have filed more than 275 letters attesting to his generosity to coworkers, friends, charitable causes and Jewish organizations. Many of the correspondents also cite Weiss’s work to sue Swiss banks and German companies on behalf of Holocaust victims.

“The ultimate success in distributing more than $7.5 billion to almost two million Holocaust victims is traceable in large part, to Mr. Weiss’s wisdom, his passion and his generosity of spirit,” a law professor at New York University, Burt Neuborne, wrote.

Among the notables urging leniency for Weiss are at least two former federal judges, Arlin Adams and Stanley Sporkin; a former White House counsel, Bernard Nussbaum, and the Nassau County executive, Thomas Suozzi. Weiss, who has endowed a loan forgiveness program for NYU law students who enter public service, also won letters of support from the university’s president, John Sexton, and the dean of its law school, Richard Revesz.

Jewish leaders touting Weiss’s philanthropy include the national director of the Anti-Defamation League, Abraham Foxman, and several officials of the Israel Policy Forum.

Perhaps inadvertently, some of the letters highlight the extraordinary wealth Weiss developed through class-action litigation. A former Argentine interior minister and defense secretary, Fernando Maurette, praised the attorney for sending his “outstanding private collection of 138 Picassos” to be exhibited for free in Buenos Aires. In other letters, family members fret that Weiss’s 97-year-old mother, who is unaware of his guilty plea, could be devastated by the news.

For years, Weiss maintained that the long-running federal investigation of his firm was retribution by the Bush Administration on behalf of corporate interests. However, the legal titan abruptly changed course earlier this year after three other partners or former partners at his law firm, David Bershad, Steven Schulman and William Lerach, offered guilty pleas.

“Looking up from the bottom of the deep pit into which I have descended has been painful,” Weiss wrote to Judge Walter last month. “My remorse is unequivocal.”

In February, Judge John Walter sentenced Lerach to 24 months in prison, the maximum permitted under his plea deal. Bershad and Schulman are scheduled to be sentenced later this year.

Some lawyers who have closely followed the case expect Weiss to get the maximum 33 month sentence allowed under the plea. Prosecutors have accused Weiss of “criminal arrogance” for discussing secret payments with an intermediary lawyer even after the investigation was well known. Weiss also admitted to withholding evidence, namely a fax which had been subpoenaed in the probe.