Lovely Argentina is home of the Pampa, the tango, and some undersea surprises, including the wreck of at least one German U-boat that crossed the Atlantic in winter 1945 and that the government may be trying to cover up.

Of course, the ocean does have a way of covering up submarines too, but in this case the remnants of a 262-foot-long wreck that was discovered in October off the coast of Quequén, a port in the province of Buenos Aires, are still making waves. That is because the U-boat may have been one of several of the Kriegsmarine’s vessels that are widely believed to have offloaded Nazi war criminals onto South American shores in the waning days of World War II. 

Government opposition leaders have dispatched a 24-page report to the Argentine president, Alberto Fernandez, in which they claim he has been stalling on an official probe of the wreck. Mr. Fernandez belongs to the Peronist faction of the Justicialist Party. Juan Perón was a known Nazi sympathizer and is said to have helped some of the worst Nazi war criminals, notably Josef Mengele and Adolf Eichmann, find refuge in Argentina during his first term as president. 

Any independent confirmation that Nazi U-boats found safe harbor on Argentinian shores would not exactly do the country’s cultural heritage proud; in fact it would almost be the very definition of a public relations disaster. 

Lest anyone think the idea of a submarine traversing thousands of miles of open ocean with 1940s technology sounds far-fetched, think again. While a German U-boat could stay submerged for only 92 miles at a time, its full traveling range was about 8,000 nautical miles, or more than 9,000 miles. The distance to Buenos Aires from Hamburg is about 7,000 miles. 

In January 1942, a Nazi submarine dubbed U-123 attacked two American ships and a Latvian freighter off the coast of North Carolina. The passenger-freighter City of Atlanta was sunk. That winter U-boats sank more than 100 ships off the eastern seaboard as well as in the Gulf of Mexico and Caribbean Sea. 

It is widely acknowledged that after Germany’s surrender, U-boat U-977 made haste for Argentina. Whether it had Adolph Hitler and Nazi gold on board might be a matter for Hollywood to sort out, but one fact is that the U.S. Navy, having eventually seized it, used it for target practice in 1946.

The man who discovered the wreck last fall is a 66-year-old Italian named Abel Basti, who heads the Eslabón Perdido, or Missing Link research group.  According to his findings, once the submarine had surfaced and whoever was on board disembarked, the vessel was scuttled with explosives. The wreckage was found 91 feet below the surface of the water and two-and-a-half miles off the coast. 

Mr. Basti maintains that once Nazi submarines had slipped into Argentina, they were routinely blown up so that Argentinian officials could cover their tracks. 

That assertion appears to fit a documented pattern. Another underwater Nazi predator, U-530, left a U-boat base at Horten German-occupied Norway in 1945 and headed to New York. After mounting unsuccessful attacks, the vessel turned south and eventually the crew surrendered at Mar del Plata, Argentina, on July 10. The crew members, first interned in America and then extradited to Britain, faced accusations of landing Nazi war criminals on Argentine soil prior to that surrender. (As for U-530 itself, an American sub torpedoed it in 1947.)

As for the Quequén wreck, Mr. Basti told the Buenos Aires Times that it was found “semi-buried, with a high-degree of destruction,” and that “some details stand out in the photos that can easily be compared with … the skeleton of a U-boat.” One of those details was a periscope. Others were SS-style lettering and “the distinctive shape attributable to a turret deflector.”  Intriguingly, he also said that “there are reports from the time that speak of a landing of Nazi hierarchs in the area.”

Argentina’s coast guard has by some estimates already spent more than $300,000 on taking images through the use of remotely operated underwater vehicles. 

Last month Mr. Fernandez announced he would not be seeking re-election. He is said to be heavily under the sway of a former president, Cristina de Kirchner, who heads the Peronist coalition. It is not clear if the pair ever made a promise for Argentina to come to terms with its Nazi-friendly past. Yet as more evidence emerges from the depths, they may find that divulging salient details in this era of social media transparency could, internationally at least, win the government more political fortune than it thinks.