Under one of the thousands of white marble crosses in the Netherlands American Cemetery and Memorial in Margarten, lies an army private from New York City, Dominic J. Arcuni, killed by the Germans at the age of 24 on April 10, 1945.

A group of Dutch World War II buffs, Stichting Missing in Action, who locate remains of the war’s “unaccounted” and memorialize the sacrifice of the forgotten, adopted his grave. Bart van der Sterren, 50, a Stichting member, reached out to amNewYork looking for help finding Arcuni’s relatives, hoping to assure his family that his grave was being well maintained, to thank the family for its sacrifice in helping to liberate Europe, and to find out more about the man in the grave he tends.

With the help of Newsday librarian Judy Weinberg, military historians and the U.S. Army 405th Infantry Regiment, 102nd Infantry Division WWII Facebook page, amNY was able to pair Stichting Missing in Action with some of Arcuni’s relatives.

The research unraveled clues as to how Arcuni — one of approximately 900,000 New Yorkers in the military during World War II — died, and solved a mystery for his relatives, who had long wondered how he was killed and where he was buried. It also revealed the crucial role Arcuni’s unit — the Cannon Company of the 405th — played in the war.

“I’ve been to Europe a half a dozen times, but I never knew he was there!” exclaimed Richard Caiati, 73, Arcuni’s nephew.

Caiati, who now lives in Westport, Connecticut, was raised by Dominic’s brother, John — one of four Arcuni brothers who served in World War II.

“The family knew he was buried in Europe, but no one knew where,” said Caiati.

“It’s so nice to finally know where he is,” added Evie Powers, 77. As a small girl, she recalls adoring visits from her dashing, fun-loving uncle, “because he just loved us so much . . . . We pray for him every Memorial Day and I have his name mentioned in church. I’m so glad someone is looking after Dominic and that other people miss him and love him,” said Powers, an artist who now lives in upstate Brewster.

Caiati became emotional when told of Stichting’s project. “This is phenomenal. It’s so great. Just knowing that these guys appreciate what our troops did,” is unspeakably moving, said Caiati.

Arcuni was one of eight children raised by Sicilian immigrant parents near Second Avenue and 106th Street. He enlisted in the Army in 1942 and married, moving to Southern Boulevard in the Bronx. (His widow, who could not be located, remarried within four years of his death.)

While Dominic had no children and his parents and seven siblings are all deceased, lore concerning Arcuni, a man of matinee idol good looks and a reliably cheerful disposition, percolated down generations of his nephews and nieces.

Records indicate Arcuni was killed in action in the vicinity of Peddenberg, Germany, on April 10, 1945 — just 20 days before Hitler committed suicide and less than five months before the end of the war.

Arcuni’s parents and siblings rarely discussed Dominic’s death because they were all devastated by it, with his diabetic mother dying “of a broken heart” afterwards, Powers recalled. But Powers and other relatives remained curious as to how he died and where he wound up.

He did not die alone, according to Jamie Robertson, 46, owner of Gillie Leather in Findlay, Ohio. In October, Robertson posted a mention of Arcuni on Facebook recalling that his now-deceased grandfather, Rod Gillis, who served with Arcuni in the cannon company, considered the jovial New Yorker his “best friend” and was with him when he was killed in an ambush.

Gillis – a taciturn Midwesterner – was endlessly entertained by the loquacious Arcuni, “a classic Italian New Yorker: always having fun, always happy,” and with whom he gobbled French fries out of helmets when the two spent 40 days in a potato field fox hole.

Gillis told Robertson that the company was driving in open trucks when they were they were suddenly enveloped in a hail of enemy gunfire. “All the troops got out and jumped in a ditch,” but Arcuni was hit, Robertson recounted.

“He fell back into the trench and my grandfather held him while he died,” Robertson recalled Gillis telling him. The soldiers then transported his body to a military hospital in Peddenberg, said Robertson.

But “why wasn’t his body brought home?” wondered Phyllis Arcuni, 47, a great niece of Dominic’s who lives in Mount Vernon.

World War II was so intense, conscripting all resources into the fight, that the military could not transport all bodies home, explained Michael Lynch, a research historian at the U.S. Army Heritage and Education Center in Carlisle, Pennsylvania.

The fallen “were buried pretty quickly, mostly in temporary cemeteries, and after the war they established more permanent cemeteries,” Lynch continued. After World War II ended, the military offered to return remains to families, but many survivors declined them. Survivors who had moved or were difficult to locate may never have been notified. In all, 8,301 Americans are buried and 1,722 missing are memorialized at Margraten and more than 218,000 remain buried or memorialized in military cemeteries abroad.

Arcuni served in a “cannon company” that used short-barreled 105 mm howitzers to provide vital fire support to infantry units, said Col. Jerry Morelock, author of “Generals of the Bulge: Leadership in the U.S. Army’s Greatest Battle” and senior historian at World War II Magazine.

Arcuni was likely part of the “tough, demanding and intense” combat in the Battle of the Ruhr Pocket that stretched from March 7 to April 21, 1945, to seal off Germany’s industrial region, the retired colonel continued.

The combat in which Arcuni was involved “was an important — really vital — contribution to Allied victory since it trapped, then defeated, the last major German army force facing the western Allies,” Morelock said.

Ed Owsian, 74, a nephew of Arcuni’s who lives in Boca Raton, Florida, pondered why, more than 70 years after the end of World War II, a group of men in the Netherlands are reaching out to get a fuller understanding of the life of a single American soldier.

That’s simple, said van der Sterren, a father of two who lives in Schinveld, Netherlands. Van der Sterren grew up near Margraten, steeped in the knowledge of the atrocities that transpired on European soil. The names on the crosses in the cemetery “are not just ‘names,’” he explained. “Those boys and girls gave their lives for Dutch freedom.”

The least he and his colleagues can do, he said, “is mention their names out loud once in a while.”