Allegations that a former Westchester district attorney, Jeanine Pirro, secretly taped telephone conversations with colleagues are prompting criticism from some who found themselves on the other end of the phone line.

Prosecutors interviewed yesterday said such conduct is unheard of among their ranks. However, local and national bar associations have been growing increasingly accepting of the practice of secretly recording telephone conversations.

“That is a wacky thing to do,” a former federal prosecutor whom Ms. Pirro taped, Mark Pomerantz of Paul Weiss Rifkind Wharton & Garrison, told The New York Sun yesterday. “One prosecutor taping another prosecutor on matters of common interest is outside the norm.”

Evidence that Ms. Pirro taped conversations was disclosed during a federal grand jury investigation, an assistant Westchester district attorney, Richard Hecht, wrote in a letter that is publicly available at the 2nd United States Circuit Court of Appeals. The extent of the taping is unclear, although Mr. Hecht wrote that “numerous other tape recordings” were discovered this year. Ms. Pirro left office in 2005 to run for state attorney general.

The only tape Mr. Hecht mentions involves two December 18, 1997, phone calls between Ms. Pirro, Mr. Pomerantz, then chief of the criminal division of the U.S. attorney’s office in Manhattan, and four of Ms. Pirro’s deputies. The topic of conversation was a late-breaking lead discovered by federal prosecutors in a murder case Ms. Pirro was prosecuting.

The lead was that an FBI informant had heard a man confess to the 1993 murder of Louis Balancio in Yonkers. Ultimately, a different man, Anthony DiSimone, was convicted of the crime, although a federal judge recently overturned the conviction on the grounds that Ms. Pirro didn’t soon enough disclose that yet another man had also been rumored to have confessed. The lead discussed in the phone conversation was turned over to the defense only this month.

Another one-time federal prosecutor who had dealings with Ms. Pirro, Kerry Lawrence, said he did not know the extent of the taping.

“If it is not unethical, it is certainly frowned upon,” Mr. Lawrence, who served as the deputy assistant in charge of the U.S. attorney’s White Plains office and is now in private practice, said. “In 10 years as an assistant U.S. attorney it is not something I ever did.”

A lawyer for Ms. Pirro said there was no impropriety involved in taping the conversations described in the transcript.

“I’ll tell you, if I was in her situation I’d have done the same,” the lawyer, William Aronwald, said. Pointing out that several people were involved in the call, Mr. Aronwald said it “makes perfect sense to record the conversation to memorialize it so that there are no misunderstandings.”

In New York, as in the majority of states, it is legal for one person to tape-record a telephone conversation without disclosing that fact.

In a 2003 advisory opinion, the New York City Bar association undisclosed taping involves “a sufficient element of trickery as to render it ethically impermissible as a routine practice.”

However, the American Bar Association issued an opinion in 2001 saying that such taping “is not inherently deceitful,” a move that reversed the bar’s stated opinion on the matter going back to 1974.

The advisory opinions contain exceptions for law enforcement personnel pursuing investigations.

Mr. Hecht accused Ms. Pirro of ordering that the tapes be destroyed when she left office, according to the letter. Mr. Aronwald said Ms. Pirro never ordered the destruction of any tapes.