Among high-profile cases in which federal prosecutors say former Allegheny County Coroner Cyril H. Wecht fraudulently billed clients were the manslaughter trial of former NBA star Jayson Williams and the California murder trial of Scott Peterson, accused of killing his wife Laci and their unborn son.

In both cases, Dr. Wecht, a nationally renowned forensic pathologist and lawyer, was called by the defense as a consultant.

Last month's grand jury presentment did not name the clients or cases, providing only dates and initials of the attorneys. In some instances, grand jurors said, Dr. Wecht billed out-of-state clients for limousine rides to Pittsburgh International Airport when he used a county car to drive there, or that he created receipts using letterhead from a defunct travel agency.

While denying any overbilling, Dr. Wecht's lawyers confirmed that two of the bills mentioned in the presentment were an Aug. 21, 2003 invoice faxed to Mark J. Geragos, defense lawyer for Scott Peterson, and a March 23, 2004 invoice to Joseph Hayden, lead defense counsel for Mr. Williams.

A jury convicted Mr. Peterson of first-degree murder in the killing of Laci Peterson and their unborn child, Connor. The Peterson case, which unfolded on cable television talk shows first as a mysterious disappearance, with suspicion building publicly around the husband, attracted nationwide attention.

Dr. Wecht and fellow pathologist Henry Lee were summoned by Mr. Geragos on Aug. 11, 2003, to examine the remains of both Mrs. Peterson and her child that had been dumped in San Francisco Bay. The two men then testified on behalf of the defense.

Mr. Geragos, who was listed in the indictment only as "M.J.G. Esq., Los Angeles, California," declined to comment on Dr. Wecht's bill.

Earlier this month, in a joint appearance on Larry King Live on CNN, Mr. Geragos defended Dr. Wecht, suggesting that any complaints of accounting irregularities could have been resolved without a federal prosecution.

"I think what the argument is, is look, if this is something that there are ethics guidelines in Pennsylvania that govern it, if this is something that traditionally has been a civil remedy, where you get sued civilly for accounting irregularities, why do you -- I mean, how do you justify [it] if in eight other cases that are similar, they went civilly, and in this case they went criminally?" Mr. Geragos said.

Mr. Geragos gave no indication that he was aware that one of Dr. Wecht's bills to him were among the counts in the indictment.

Mr. Williams, a former star with the New Jersey Nets, faces a retrial on charges that he shot and killed a limousine driver inside his Milford, N.J. home. The first attempt to prosecute him ended in a split verdict, with a jury deadlocking on a charge of reckless manslaughter.

Joseph Hayden, of Roseland, N.J., Mr. Williams' defense lawyer, retained Dr. Wecht to examine forensic evidence.

The presentment against Dr. Wecht also refers to a March 9, 2005 "facsimile of false expense reimbursement invoice" sent to an attorney identified only as "D.E.B., Esq., Reserve, La."

Daniel E. Becnel, a prominent product liability lawyer, said he is the "DEB" referred to in the indictment and that the billing was for an appearance Dr. Wecht made before a panel of lawyers in Las Vegas last year.

The forum was called by attorneys planning to represent plaintiffs in their lawsuits against Merck & Co., the makers of Vioxx, an arthritis medication linked to heart attacks in some users.

Mr. Becnel said agents "asked me whether I knew he used a county car for somebody to drive him to the Pittsburgh Airport," for the Las Vegas trip. "He charged me for it, but I don't think it was $30 or $40."

Dr. Wecht's subsequent indictment apparently ruled him out as a potential expert witness in the Vioxx cases.

"There's no question he would have been a critical witness to me in all of my Vioxx cases," Mr. Becnel said.

Another lawyer contacted by federal agents during the investigation said he was puzzled about why they believed Dr. Wecht might have cheated him.

David J. Guarnieri, a Frankfort, Ky., attorney hired Dr. Wecht in 2002 as an expert witness in a homicide case brought against D.L. Doss. Mr. Doss was accused of shaking his infant daughter to death, a charge Dr. Wecht said was not supported by forensic evidence.

A jury split 6-6 on the charges and Mr. Doss was later permitted to plead to a lesser charge.

"I couldn't get anyone locally who was willing to testify against the state medical examiner's office," Mr. Guarnieri said. "At least in my case, if they are looking for fees he charged for professional services, they're barking up the wrong tree. His fees were very reasonable."

Mr. Guarnieri said FBI agents were curious about whether Dr. Wecht billed him for transportation to the Pittsburgh airport. He said he had no recollection, and the charges cited refer only to a "facsimile of fee schedule for private services re B.P.D. [the child's initials], deceased."

Grand jurors alleged that in some instances, Dr. Wecht used his county car to travel to Pittsburgh International Airport to catch flights for private business, then billed those clients for a non-existent limousine ride.

"A limousine ride was what they seemed to be all hung up about," Mr. Guarnieri said.

One instance of prosecutors citing a fake limousine receipt as part of the wire fraud charges was a Oct. 7, 2002 fax sent to "E.E.H., Esq., Raleigh, North Carolina." That was Edward E. Hollowell, a prominent North Carolina liability lawyer and past president of the American Health Lawyers Association.

Mr. Hollowell said Dr. Wecht's bill was connected with his appearance that year as a speaker at the annual Health Law Forum in Greenville, N.C.

"Cyril is a very competent person," Mr. Hollowell said. "He's probably the most sought-after speaker in the country. I've known Cyril for 30 years and from what I know his integrity is impeccable."