After months of investigation, Western officials can't prove Russia blew up the Nord Stream pipelines.
While they can't name Russia as the culprit, officials say the attacks illustrate what Russia can do.
The vulnerability of undersea infrastructure, like pipelines and data cables, is a growing concern.
Four months on, investigators are unable to prove Moscow was behind the attack, but officials say the explosions illustrate the threat malign actors — especially Russia — pose to vital undersea infrastructure.
Despite the uncertainty, the attack has only added to concern about threats to undersea infrastructure, particularly cables and pipelines, that connects continents and powers economies.