Brian Walshe’s bizarre claim that his wife, Ana, died of “natural causes” at age 39 “defies common sense,” a Massachusetts prosecutor said Friday as the murder trial wound to a close.

Walshe, 50 — who is on trial for murdering the mother of his three children on New Year’s Day 2023 — dismembered and disposed of her remains in dumpsters “to hide the fact that he murdered Ana,” prosecutor Anne Yas told the jury in Norfolk County Superior Court in Dedham, Mass.

Her body has never been found.

“He could not let Ana’s body be found because Ana didn’t die of natural causes,” Yas said. “The defendant didn’t want anyone to find Ana’s body, to find out how she died.”

The 12-person jury began deliberating Friday afternoon whether Walshe is guilty of a single count of first-degree murder — a conviction for which would result in life in prison without parole.

The jurors could also choose to convict Walshe — who didn’t testify and didn’t call any witnesses — of second-degree murder, which also carries up to life in prison but offers parole.

They must come to a unanimous verdict and must be convinced beyond a reasonable doubt of Walshe’s guilt.

Walshe’s lawyer, Larry Tipton, told jurors during his closings that the 39-year-old mom died of “sudden unexplained death” after Walshe, Ana and a close friend rang in the New Year together with champagne at their Cohasset, Mass., home.

After the friend left and Walshe cleaned up the kitchen, he claimed he went to their bedroom and found the unthinkable — that Ana had suddenly died without explanation, causing him “confusion, panic and fear,” Tipton said.

Worrying that he would be blamed and his sons would be left with a dead mom and imprisoned dad, Walshe frantically began carrying out “troubling, horrific” actions in the following hours and days to cover up her death, the defense attorney argued.

Tipton admitted Walshe’s disturbing online research, beginning in the early morning of Jan. 1, 2023, “causes chills, it causes disgust.”

Jurors were presented with evidence that Walshe searched how to dismember a body, the best way to dispose of a body, and even researched serial killer Patrick Kearney, the so-called “trash-bag killer.”

“Look at all of those searches, think of how they evolved,” Tipton said. “Consider how they go from one subject to another in a rapid fashion — searches conducted by a man who is in disbelief and confusion.”

Tipton said there was “no motive,” and no evidence that Walshe was planning to kill Ana. He claimed the pair loved each other, and on their last night together, their friend Gem Mutlu testified, they were “festive” and “jovial” and appeared like a couple in love.

“What would cause a loving husband and a loving father to do the things that you’ve heard about in this case?” Tipton asked. “Could it be something that was sudden, something that was unexpected, something unbelievable … something that is terrifying, something that defies logic?”

Tipton also argued that if Walshe had planned to kill Ana ahead of time, it made no sense that he made all those damning internet searches after her killing.

Yas, who delivered her closings after Tipton, fired back: “This defendant caused Ana’s death.

“That Ana Walshe died of natural causes defies common sense.”

Ana was a healthy and fit woman, who worked out regularly and showed no signs of being sick, Yas said.

“[Walshe] didn’t just want her dead, he needed her dead. This was a marriage in crisis that was heading toward a breaking point,” Yas said.

Jurors heard testimony that Ana and Walshe’s marriage was strained because of the husband’s federal art fraud conviction, for which he was stuck on home confinement in their Cohasset home taking care of their three sons, while Ana worked a high-powered real estate job in Washington, DC.

Walshe also owed over $400,000 in restitution and was facing prison time.

And Ana struck up a romantic relationship with a man in DC, William Fastow — which prosecutors claim Walshe found out about and was part of the reason he wanted to kill her.

Ana’s best friend, Alissa Kirby, told jurors Wednesday that Ana confided in her that she hadn’t slept with Walshe in over a year and she was “falling out of love” with him.

“The defendant was going to lose Ana and if he lost Ana, he would probably lose his freedom,” Yas said. “He lulled Ana into thinking everything was OK. He didn’t want her to realize that he was aware of the relationship [with Fastow]. He wasn’t going to let Ana know that she wasn’t safe.”

Tipton claimed that Walshe didn’t know about the affair and wasn’t the jealous type anyway. And that in spite of his federal case, Walshe and Ana weren’t actually struggling financially as they had bought and sold several investment properties and prepared to protect the family assets the best they could.

Jurors saw videos of Walshe going into Home Depot and Lowe’s to buy cleaning products and tools to carry out his grisly task, including a hatchet, hacksaw and Tyvek suit.

He then took apart her body, put it in bags and placed those bags in dumpsters, including one by his mother’s home, prosecutors argued.

Jurors were shown evidence that investigators recovered from that dumpster, like bloodstained pieces of a rug and the tools Walshe bought.

Walshe then wove an elaborate tale that Ana had left abruptly for DC on New Year’s Day for a work emergency and disappeared — a story that led police in both states on a wild goose chase.

Walshe surprisingly pleaded guilty just weeks before trial to the only other two charges in the case: lying to cops and disposing of the body. He maintained his innocence on the count of murder.