The intensifying presentencing battle between the NBA and Tim Donaghy continued yesterday when the league filed a letter rebutting charges made last month by the fired referee's attorney.

Richard W. Buchanan, the league's general counsel, said in a letter to U.S. District Judge Carol Amon that the NBA had cooperated fully with the federal investigation and that it could find no referee other than Donaghy guilty of any serious wrongdoing.

"The NBA has received no information that any referee other than the defendant bet on NBA games or engaged in criminal activity with respect to NBA games," Buchanan wrote.

Buchanan specifically cited claims made by Donaghy's lawyer, John Lauro, in a May 19 presentencing letter to Amon. He did not address more recent accusations made by Donaghy in a supplemental letter filed on Tuesday.

In the May 19 letter, Lauro suggested the league pressured the U.S. Attorney's Office to shut down its investigation and to make sweetheart deals with Donaghy's codefendants, James Battista and Thomas Martino.

The three, all classmates at Cardinal O'Hara High School in Springfield, have pleaded guilty to a variety of gambling charges. Only Donaghy pleaded to more serious wire-fraud charges.

All will be sentenced next month. Battista and Martino face sentences of between 10 and 16 months, while Donaghy could get up to 25 years in prison.

Buchanan denied those accusations and said that during the negotiations that led to the plea agreements, the NBA had no "substantive communications" with federal authorities.

On Tuesday, Lauro's supplemental letter listed additional information Donaghy had provided federal investigators, including allegations about improper conduct by other NBA referees.

It detailed "improper interactions and relationships" between referees and league players, coaches and officials. Lauro's letter also said Donaghy told authorities about casino gambling by other referees, in violation of league guidelines.

Donaghy charged that the league had tampered with a playoff series in 2005 by advising officials to more closely monitor play around one of the team's star players. He also said two referees intentionally helped extend a 2002 playoff series by calling an excessive number of fouls against the team winning the series, three games to two, while ignoring ones committed by the trailing team.

Buchanan did not acknowledge those claims except to say that the NBA knew of referees who had bet in casinos or on other sporting events. He said Donaghy was the only one who bet on NBA games or provided inside information on them.

A source familiar with the case said this increasingly nasty exchange between Lauro on one side and prosecutors and the NBA on the other began with the May 19 letter, which the source characterized as "unusually scathing."

Originally, the source said, the NBA had not sought any restitution from the referee, who was fired in July after a 13-year career. After that letter, the source said, league executives changed their minds and asked that Donaghy be made to pay $1 million.

That, in turn, led to Lauro's Tuesday letter, in which Donaghy provided more details about alleged wrongdoing by the league and other referees, allegations the league denied.

"I really can't understand what Lauro is trying to do," said the source. "It's great to want to get a lighter sentence for your client. But he seems to be trying to do that by attacking the victim. It's the damndest thing I've ever seen."

Lauro did not immediately respond to phone and e-mail messages.

Buchanan also denied that the NBA had rejected Donaghy's offers to provide the league with information related to what he'd told federal authorities about his case.

Contact staff writer Frank Fitzpatrick at 215-854-5068 or ffitzpatrick@phillynews.com.