More than 15 years ago, when the Nord Stream gas pipeline between Russia and Germany was little more than an idea, a Swedish government study warned of the risks inherent in running a critical piece of energy infrastructure along the Baltic Sea floor.“The key question is not what kind of surveillance there was, but why the lack of surveillance for this pipeline — and other pipelines and electric cables and the underwater cables on the seabed,” said Niklas Rossbach, deputy research director at the Swedish Defense Research Agency.“In the big context of the war in Ukraine that is ongoing, it’s very interesting and very serious,” he said of the blasts, repeatedly emphasizing growing threats from Russian spycraft and cyberattacks.Even the decision by the Swedish government to keep details of its inquiry secret from Western allies has prompted whispered speculation that perhaps investigators have cracked the case and are strategically keeping quiet.“But hopefully we will.” As for his government’s choice to keep its cards close, Mr. Stenling said: “The entire investigation is unusual.” Nord Stream encompasses two projects, each a pair of concrete-encased steel pipes nearly four feet in diameter and more than 700 miles long."