Ending months of speculation, St. Tammany Parish Sheriff Jack Strain said Wednesday that his office has found no basis to arrest Kacie Breen, who fatally shot her husband Wayne Breen twice in the early morning hours March 1 during what she said was a ferocious argument.

The announcement means the case moves to District Attorney Warren Montgomery, who will decide whether enough evidence exists to put the case before a grand jury for a potential indictment.

Montgomery issued a short statement Wednesday afternoon saying his office will review the “voluminous” case file before deciding how to proceed.

Kacie Breen has never been arrested in the shooting, and indications throughout the sheriff’s four-month investigation were that she would not be.

During a news conference shortly after the incident, Strain said there was evidence that a “violent altercation” occurred before the shooting. Months later, a spokesman indicated that Kacie Breen had been cooperative during the investigation.

Strain’s statement Wednesday said his detectives interviewed dozens of people, collected thousands of pages of documents and examined forensic and electronic evidence.

The key points of what happened that night in the couple’s Folsom-area home are not in dispute. They had gone to bed but at some point woke up and began arguing. That argument ended in the garage, where Kacie Breen shot her husband twice. She called 911 and later told detectives that she had feared for her life. She declined medical treatment.

Not surprisingly, Kacie Breen’s attorney, Richard Ducote, was pleased with Strain’s announcement. “Obviously, they did an exhaustive analysis of the evidence and made the right decision,” Ducote said.

An attorney for one of Wayne Breen’s sons by his first marriage, Sean Breen, said his client was disappointed. “But we will reserve further comment on the investigation until the DA’s Office has made its final determination,” René Frederick said in a statement.

Wayne Breen’s brother Bobby Breen was incredulous.

“I read the sheriff’s statement with astonishment,” he said. “The fact that no probable cause was found in the case was, to me, unbelievable.” He promised to make a longer statement later in the week.

Although Kacie Breen won’t face criminal charges — at least for the moment — her legal battles are just beginning. She and her husband’s five grown children from his first marriage have already been in court multiple times to spar over his will. A recent deal will put an independent third-party administrator in charge of the estate while the legal tussling continues.

At the same time, Sean Breen has filed a wrongful-death suit against Kacie Breen. In that case, Ducote, her lawyer, is drawing a picture of Wayne Breen as a habitual liar and philanderer who was prone to fits of rage.

In one court filing, Ducote alleged that Wayne Breen was driven into a rage the night he was killed because of questions about his military service. He had told people that he had served in combat in Vietnam, when in fact he had never been to Vietnam and had never seen combat, Ducote said. In a bizarre twist, Ducote alleged that Breen used his Vietnam stories to help seduce women.

He also blamed his Vietnam experiences for the fits of rage to which he was prone, Ducote said, adding that St. Tammany Parish Hospital had ordered him to attend therapy to help him deal with his anger.

Ducote presented more evidence Wednesday, including a copy of Wayne Breen’s service record in the Marines, which indicates he spent most of his enlisted time in California, New Orleans, Lafayette and Gulfport, Mississippi.

The documents collected from his office also include a 2007 letter from hospital administrators to Dr. Leanne Truehart, Wayne Breen’s therapist, thanking Truehart for evaluating him and providing a list of recommendations. The letter also offered to pay for Truehart’s ongoing anger management treatment of Breen as long as she provided periodic reports.

In his earlier filing, Ducote had said that Breen was forced to seek counseling by hospital administrators in 2006 because of his “abusive and derogatory behavior toward the nursing staff.”

A hospital spokeswoman declined to comment, citing a confidentiality policy.

The letter was collected, along with several boxes of material, from Wayne Breen’s medical practice office in the weeks after he died, Ducote said. Some of the documents seem to indicate that Breen’s outbursts went back even further.

One incident is the subject of a seven-page handwritten letter from Bridget Breen, Wayne’s eldest child from his first marriage. In the letter, she recounted an altercation involving her brother Ryan that happened in early January 2002.

“When I think of the look in your face at that moment Dad, I didn’t know who you were and I don’t know how Ryan could have possibly caused all of that,” Bridget Breen wrote to her father. “That was a horrible, frightening moment and every time I think of it I feel physicall(y) ill.”

The letter begged Wayne to work with his wife — whom he later divorced — to help get control of his relationship with the couple’s four sons.

“Please fix it, Dad,” Bridget wrote. “Could you and mom try to fix it together? Maybe set time aside for just the 2 of you and talk about expectations for each other and talk about discipline together, not in the heat of the moment, but in loving each other and us?”

Through her attorney, Bridget Breen declined to comment on the letter. The attorney, Frederick, confirmed the letter’s authenticity but called its release “offensive” and said it “smacks of desperation.”

The other items Kacie Breen collected from Wayne Breen’s office included what her attorney called evidence of Wayne Breen’s obsessive and at times violent behavior. There were binders of emails between Kacie and others, including a man with whom she was having an affair — emails Ducote said Wayne Breen collected by installing a software tracking program on her computer.

Other items include GPS trackers that Ducote said may have been used on Kacie’s car and a device to record phone calls.

Ducote said a jealous Wayne Breen collected pairs of his wife’s underwear and tested them for seminal fluid. Kacie Breen found a pair of her underwear sealed in a plastic bag with a testing kit in Wayne Breen’s office, Ducote said. There are microscope slides labeled with a red K that Ducote said may contain samples taken from Kacie Breen’s clothes.

Wayne Breen’s jealousy wasn’t entirely misplaced. Ducote acknowledged that Kacie Breen had an affair that only ended in 2010 after Wayne Breen confronted her about it.

Frederick, the attorney for Breen’s children, said that even if all of what Ducote says is true, it doesn’t amount to much. Given that Kacie Breen admitted to an affair, her husband may have had a reason to be suspicious, Frederick said.

As for Wayne’s outbursts with his family and at work, Frederick said incidents in 2002 and 2007 “absolutely are not relevant” to what happened in the couple’s home on March 1.

Follow Faimon A. Roberts III on Twitter, @faimon.