Sometime Saturday night, physician Wayne Breen and his wife went to sleep watching television in the bedroom of their home, set on 31 picturesque acres near Folsom, a quiet area dotted with horse farms and ranches. However, the couple’s peaceful night was shattered about 2:30 a.m., when they woke up and began arguing.

By 3 a.m., the 65-year-old obstetrician had two bullet holes in his chest, and his wife was calling 911 to report that she had shot him.

Breen was pronounced dead at the scene by the St. Tammany Parish Coroner’s Office.

When detectives arrived, they found “obvious signs” of a domestic dispute, St. Tammany Parish Sheriff Jack Strain said Monday.

Kacie Breen, the dead man’s 42-year-old second wife, was taken to the Sheriff’s Office, where she told detectives the pair had been arguing and the dispute escalated into a “violent altercation” that ended when she shot him, Strain said.

There was no word on what the argument was about.

The Coroner’s Office ruled the death a homicide, but Kacie Breen has not been booked in her husband’s death while detectives explore whether the shooting was done in self-defense, Strain said.

The shooting was the latest in what Strain described as a “history of domestic disturbances between the pair.” Court records show that Kacie Breen filed for a protective order against her husband in July 2012. That record is sealed, but Strain said the order had expired.

He did not provide any other examples of problems between the two, and online records in St. Tammany Parish do not show any further arrests for Wayne Breen or court filings between the pair, who had a 7-year-old son.

The boy was in the house at the time of the shooting, and detectives plan to speak with him, Strain said.

Detectives now are focused on sifting through physical evidence to see whether it aligns with Kacie Breen’s account, he said.

Wayne Breen was an obstetrician and gynecologist affiliated with Doctors for Women Medical Centers in Covington. Patients and colleagues recalled him as a good listener and a good doctor who took time to visit with his patients.

Many of them took to his clinic’s Facebook page to express their response to his death.

“My heart is so broken and I can’t believe this happened to such a good doctor,” wrote Sandra Abadie Johnson.

Katie Ricks echoed those sentiments. “I am so heartbroken over the loss of such a great man. Dr. Breen was so caring,” she wrote.

Others took to Twitter.

“Brokenhearted at the untimely death of the best doctor I’ve ever had. Rest in peace, dear Dr. Breen,” Debra Kreeger tweeted. Reached by phone, Kreeger said she had been a patient of Breen’s for nearly a decade after moving to Covington and asking local friends for a recommendation.

“I was asking around, and every single one mentioned him,” she said. “I knew him as someone who really took time with his patients.”

Another patient, Rose Dominguez, said Breen had helped her deliver her two children in 1986 and 1987 and she had remained his patient.

“He was very nice, very caring,” she said. “He was always there if you called.”

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