The highly unusual search of a defense attorney’s offices at the request of the prosecution has triggered a vigorous legal fight in a lurid Frisco murder-for-hire case.

Attorneys for Mark Lyle Bell — with support from the Texas Criminal Defense Lawyers Association — angrily accuse the Collin County district attorney’s office of violating constitutionally guaranteed attorney-client privilege.

“I think it’s unconscionable,” said David Schulman of Austin, one of the attorneys for Mr. Bell, who is accused of being the triggerman.

Prosecutors in the death penalty case defend the search, saying they had strong indications the defense was hiding evidence, including the boots Mr. Bell wore the night of the killing.

“No one has a right to conceal evidence in a criminal case, including attorneys,” said Greg Davis, first district assistant attorney.

The after-hours search in February didn’t turn up the boots but did yield a sealed box, documents and handwritten letters from Mr. Bell to his wife.

In a jailhouse letter intercepted earlier, he asks her to mail him razor blades and poison he could use to commit suicide if his escape plans fail.

“I wonder how long it would take a 220-pound man to bleed to death if both ankles and wrists are cut?” the letter says.

No trial date has been set in the capital murder case, in which Mr. Bell is accused of gunning down 42-year-old Craig Nail in his Frisco home on Dec. 26, 2007.

Authorities allege that Mr. Nail’s estranged wife, Vera Elizabeth Guthrie-Nail, wanted him dead. She and another man, Thomas Edward Grace, face charges of conspiracy to commit capital murder. All three defendants remain in the Collin County Jail.

The controversy is focusing now on State District Judge Mark Rusch, who signed the warrant to let Frisco police and Texas Rangers search the McKinney office of another defense attorney, Keith Gore. Mr. Bell’s attorneys want the judge removed from the case.

Members of the Texas Criminal Defense Lawyers Association plan to be at an Aug. 5 hearing on the request for Judge Rusch’s recusal.

“I thought it was pretty outrageous to issue a search warrant for a lawyer’s office,” said Craig Jett, the association’s immediate past president. “A defendant has a right to have his communication with his lawyer be private.”

Judge Rusch declined to comment, but the Texas attorney general’s office says he should not be taken off the case. It also says the judge shouldn’t be forced to testify at the hearing.

The attorney general filed a motion in support of Judge Rusch on Monday. The document did not address whether he acted properly in granting the search warrant; instead, it says that “prior issuance of a search warrant or review of evidence by a judge is not a basis for recusal.”

Mr. Bell’s attorneys strongly disagree. They say Judge Rusch would be biased because he has seen evidence that could be used against Mr. Bell.

“Judge Rusch knows facts about the Defendant and his potential defenses that he should not know,” attorneys said in their June motion to recuse the judge.

Linda Eads, a law professor at Southern Methodist University, said lawyers can be subject to a search warrant.

“They do not get to hide the fruits of a crime,” said Dr. Eads, a former federal prosecutor. “There’s absolutely no prohibition of having a search of an attorney’s office.”

However, she said, such search warrants are rare and are considered an extreme measure to obtain evidence.

Dr. Eads said courts must balance “the level of probable cause against the incredible importance of the attorney-client relationship.”

Mr. Gore, the lawyer whose office was searched, declined to comment.

The district attorney’s office subpoenaed him to appear earlier in the year before a grand jury investigating the case, but he declined and appealed the subpoena to State District Judge Robert Dry.

Judge Dry set a hearing for last March 4 for the prosecution and defense to make arguments about turning over evidence. Four days before the hearing, however, the district attorney’s office obtained the warrant from Judge Rusch to search Mr. Gore’s office.

The prosecution did an “end-run around Judge Dry’s procedure for providing due process,” the defense argues in its motion to recuse Judge Rusch.

The district attorney’s office counters that Mr. Gore told Judge Dry he wouldn’t turn over evidence even if the judge ordered him to do so.

“A search warrant is really the last option you want to use in any case,” said Mr. Davis, first assistant district attorney.

The defense denies that Mr. Gore told Judge Dry he wouldn’t comply with an order to present evidence.

“Attorney Gore had every intention to comply with any lawful court order issued after receiving a proper hearing where his Client’s rights could be protected,” according to a document filed Thursday.

The document says Mr. Gore never had the boots that prosecutors say Mr. Bell wore during the crime.

Prosecutors say Mr. Bell’s wife, Linda Bell, told Frisco police she gave the boots to Mr. Gore. But the search of his office didn’t uncover them.

“We don’t know where they are,” Mr. Davis said.

Prosecutors contend that Mr. Nail’s slaying was supposed to have been staged as a murder-suicide.

He was shot multiple times Dec. 26 in the top floor of the Frisco home he had shared with Ms. Guthrie-Nail before they separated. His girlfriend, TherisaÖ HofmanÖ also was shot several times but managed to get to a neighbor’s house, from which police were called.

The Nails had been separated throughout a bitter divorce case, which was filed in May 2006 and was near an end. Ms. Guthrie-Nail lost the house and primary custody of their 6-year-old daughter.

According to arrest warrant affidavits, Ms. Guthrie-Nail never met Mr. Bell. All contact, the affidavits say, was arranged by a group called Bikers Against Child Abuse.

Mr. Bell has a criminal history of burglary, forgery and theft in the 1980s and ’90s. No Texas criminal records were found for Ms. Guthrie-Nail or Mr. Grace.

In a three-page jailhouse letter to his wife, Mr. Bell talked about committing suicide if he couldn’t escape.

“I accept death with open arms because in here I’m dead regardless,” he wrote.