Anne Arundel County’s top prosecutor likes to try big cases herself, so she took the lead when her office charged a former Navy doctor with stabbing his wife to death in their waterfront apartment in Edgewater last summer amid the unraveling of their polyamorous relationship.

James Strachan Houston, 58, sustained severe cuts and stab wounds during the Aug. 9 encounter with his estranged 47-year-old wife Nancianne Houston and was flown to the Maryland Shock Trauma Center, where he underwent surgery.

But prosecutors think he used his medical knowledge to wound himself, making his injuries look like they were the result of a knife fight, without actually risking his life. After he was released from the hospital, police arrested him and charged him with murder.

Anne Arundel County State’s Attorney Anne Colt Leitess, who prosecuted the Capital-Gazette mass shooting trial, took this case herself, but was thrown off it Tuesday by a circuit court judge who found she failed to disclose evidence favorable to the defense — that the defendant’s wife once allegedly pulled a knife on him — among other prosecutorial missteps.

Circuit Judge Mark W. Crooks said the information Leitess withheld was “unequivocally” evidence that could be considered exculpatory — potentially showing a defendant’s innocence — and was required to be disclosed, particularly considering that Houston‘s attorneys say he was defending himself from his estranged wife.

“It’s the state’s principal responsibility to achieve justice, not secure convictions,” said Crooks, citing the American Bar Association‘s Special Rules for Prosecutors.

Leitess, who was not present for Crooks’ ruling, could not be reached immediately for comment.

The development marks the latest public stumble for Leitess, whose recent prosecution of a man accused of shooting six neighbors, three fatally, in a dispute over parking, ended in a mistrial after a judge ruled Leitess made “several transgressions” while cross-examining the defendant.

Defense attorneys declined to comment on Crooks’ ruling.

The story of the Houstons’ marriage and its violent end is still scheduled to unfold over an approximately two-week trial scheduled to begin May 23. The removal of Leitess from the case raises the question of whether there may be a delay.

In a pretrial hearing Monday, Leitess acknowledged she should have disclosed the information.

Crooks dismissed her effort to blame detectives in the case for not following her orders related to the information. She wanted them to conduct a recorded, follow-up interview with the source of the information.

“That blame game made no sense,” Crooks said. “The state’s attorney is the chief law enforcement officer in any county. The buck stops with her.”

The potentially exculpatory information came up April 1 when Leitess called a neighbor and friend of Houston, Steven Valladares, during routine witness preparation. Towards the end of the conversation, Valladares told Leitess that Houston once told him Nancianne pulled a knife on him during a dispute — and that he had told police as much.

Valladares testified that Leitess became combative when he told her about the knife incident.

“First, I was told it never happened that I contacted detectives,” he recalled, adding that he felt he was “being prosecuted.”

Two police detectives testified Monday that they didn‘t recall being told about previous knife incident, though one acknowledged Valladares relayed some additional information in a call days after his first interview, which was recorded in August.

Police used some of that information — about potential video cameras in the Houston‘s apartment — to get a search warrant, but did not identify the source as Valladares and did not mention anything about a prior knife incident.

Valladares’ subsequent interaction with Leitess in April left him with a bad taste and he decided to call Houston‘s defense attorneys. He spoke to Robinson the same night.

Leitess testified she was surprised by Valladares’ disclosure and disputed that she became combative, saying he reacted with hostility when she asked follow-up questions. She said she questioned whether he was being truthful because he couldn‘t remember what officer he told, and there was no record of it.

The state’s attorney said she knew she had an obligation to disclose the information to the defense, and that she intended to, but disputed that it was exculpatory.

“Should this information have been given two weeks ago? Absolutely,” said Leitess, adding she was concerned someone had “gotten to” Valladares.

“The information was going to be provided,” said Leitess, without answering when she planned to turn it over. “The delay is regrettable but the intent was to record [Valladares].”

Crooks called it “incredibly troubling” that Leitess did not immediately disclose potentially exculpatory evidence, as required by law.

Briefed on Houston‘s case, defense attorney and former prosecutor Andrew I. Alperstein said Leitess’ intent did not absolve her legal obligation.

“It sounds like once the discoverable statement was made, the prosecutor did what she was supposed to do and memorialize it — her instinct was to do that, but it didn‘t happen. The police didn‘t do that. The state’s attorney didn‘t do what she was supposed to do and disclose it,” Alperstein said in an interview.

Crooks also admonished Leitess, saying it was “poor practice” for her to have spoken to Valladares and approximately 14 other witnesses without anyone else present.

Alperstein said it defies best practice for an attorney to speak to a witness alone — especially in a case as significant as a homicide.

Crooks said such interviews “irreparably” made Leitess a witness in the case.