A cash-strapped ex-NYPD cop who’d just bought his wife a pricey Louis Vuitton handbag for Christmas flipped under the financial stress of the holidays and killed her, police sources said yesterday.

“I just shot my wife,” muscle-bound Clarence Cash, 49, calmly told officers hours after allegedly pumping 10 bullets into his pretty wife, Tracey Young, 42 — a top tax investigator who specialized in busting tobacco smugglers — in their posh Queens condo.

Detailing the gruesome deed — which included blasting Young three times in the face — Cash added, “My wife, she didn’t deserve that.’’

Young’s own mother was murdered by a lover when the tragic tax cop was a child, a neighbor said.

After Cash punched Young in their fight over dough, she threatened to leave him — sending him further over the edge, law-enforcement sources said.

Neighbors admitted that they had heard Young and Cash arguing, then loud bangs — but none ever called cops, even though at least one of them suspected gunfire.

After allegedly killing Young at around 10:30 p.m. Saturday, Cash — a body-building, part-time guard at the federal courthouse on Pearl Street — fled the couple’s apartment at 143-41 84th Drive in Briarwood.

He told cops he wandered the city for more than seven hours trying to work up the guts to commit suicide.

“He took her gun and went to Rockaway Beach to kill himself,” said Queens Assistant District Attorney Robert Hanophy Jr. at Cash’s arraignment last night.

Instead, Cash turned himself in at the Midtown South Precinct at about 6 a.m. yesterday, handing over two handguns — his Glock and her registered Sig Sauer, the sources said.

“I’m a retired cop,” he said before describing his heinous crime and sniveling, “I tried to kill myself, but I couldn’t do it.”

One law-enforcement source said Cash “appeared calm, gentlemanly” when he showed up.

“He was remorseful — just came in and said he wanted to speak with a detective,” the source said.

Cash was charged with first-degree murder. He was remanded without bail, and his lawyer asked that he be placed in protective custody at Rikers.

Neighbors said the couple, who were married a few years ago and had no kids, was last seen arriving home in Cash’s black Mercedes at about 9 p.m. on Saturday. They appeared happy, witnesses said.

“They seemed fine when they got on the elevator,” one neighbor said.

Building resident Maple Dong, 28, said Young had recently told her Cash “bought a lot of gifts for her for Christmas,” including the handbag.

“She said, ‘I asked for it, and he bought it for me,’ ” Dong recalled.

But Cash apparently had trouble affording it — he’d been slapped with federal tax liens, multiple civil judgments and warrants from New York state for failing to pay back taxes dating to at least 1998, public records show.

Cash confessed to authorities that what had started as a romantic night for the pair went horribly awry within minutes, Hanophy said.

“We went to get food,” Cash recalled, and returned to the condo.

“I lit some candles, and I rubbed cream on her back.’’

But the pair soon started fighting, one law-enforcement source said.

“The holidays are coming, and they didn’t have enough money,” the source said.

Shortly before 10 p.m., Young desperately called her sister, April Young, in The Bronx saying she was coming over.

A half-hour later, Tracey texted her sister that her iron-pumping hubby — who had to wear custom-made suits to fit his beefy frame — had hit her.

“When we were arguing, she mushed me in the face, and I punched her,” Cash allegedly told cops.

A furious Tracey Young told Cash “she was going to leave him’’ — and he whipped out a gun and began blasting, sources said.

Cash later told authorities he thought he shot her only three or four times.

Meanwhile, April Young raced to the couple’s eighth-floor apartment, where she rang the bell but got no answer.

The panicked sister went to the apartment next door, where a woman said she had heard what she thought were gunshots at about 10:30 p.m. The woman’s husband didn’t think they were shots, and neither called 911.

Another neighbor told April she heard four to six loud bangs but also didn’t think they were gunshots and never called police.

April called 911 at 11:09 p.m.

Cops entered the couple’s blood-splattered apartment and found Young shot three times in the face, twice in the back, once in the left breast, twice in the right side and once in each armpit. Thirteen shell casings from a 9mm handgun and three bullet fragments were recovered.

Cash had three licensed firearms: two Smith & Wessons and the 9mm Glock. Tracey Young had the 9mm Sig Sauer semiautomatic.

Cash had retired from the 32nd Precinct in Harlem in 2006 and was working part time for the Marshal’s Service, escorting prisoners to the Pearl Street courthouse from their holding cells.

“The guy is huge. He’s like one big muscle,’’ another source said. “He’s very health conscious. He works out all the time.”

The co-worker said Cash was always given the toughest assignments involving gang members, who would taunt him.

“But he never lost his cool, not even once. He was the mellowest guy I’ve ever seen,” the source said.

Another police source said Cash has an 18-year-old son from a previous relationship.

“He loved him to death,” the source said.

“[Cash] is a good guy,” the pal added. “He was friends with everyone.”

Cash had no arrest record but was involved in domestic incidents in January 2003 and March 2011. In each case, the complainant was another woman, who complained to cops in the 105th Precinct in eastern Queens.

Young, an investigator since 2002 with the state Department of Taxation and Finance, was an ace undercover who specialized in cigarette smuggling, her bosses said.

“She was great on the streets in gaining informants,” said Tom Stanton, her supervisor for six years before he retired in 2010.

Neighbors said Young, president of her homeowners board, was always willing to help out at home.

“She was very dedicated to the building. She just did the Christmas decorations,” said a neighbor who identified herself only as Agnes.

Agnes’ husband, Martin, said of Cash: “He was a quiet guy, very friendly. It’s a shock . . . He always called her ‘my sweet lady.’ ”

Cash’s lawyer, Sam Braverman, who knows his client from his work at the federal courthouse, called the situation “tragic.”

“[Cash] is an excellent, excellent law-enforcement officer,” Braverman said.

Cash’s next court appearance in set for Jan. 3.

Murder timeline

9 p.m. Saturday

Neighbor walking his dog sees Tracey Young and her husband, ex-cop Clarence Cash, arrive home in their black Mercedes.

9:55 p.m.

A panicked Young calls her sister, April, to say that she and Cash were fighting and that she would be coming to her house.

10:28 p.m.

Tracey Young text-messages her sister that Cash hit her.

10:53 p.m.

April Young rushes to her sister’s condo, but there is no answer at the door. Next-door tenants tell her they heard arguing and what sounded like gunfire at around 10:30 p.m. but never called the cops.

11:09 p.m.

April Young calls 911, and cops discover her sister’s body shot 10 times.

6 a.m. yesterday

Cash turns himself in at the Midtown South Precinct and surrenders two guns. He allegedly makes a full confession.

Additional reporting by Reuven Fenton, Jamie Schram, Josh Saul, Bruce Golding and Julia Marsh