How did divers manage to blow up the Nord Stream pipeline? We went down to the spot to find out

It was an event that rocked Europe and shook world affairs. 

Early in the morning on Sept. 26, 2022, a series of powerful undersea explosions damaged pipelines under the Baltic Sea near Denmark that carried Russian natural gas to Germany. 

Fingers were immediately pointed at Ukraine, which had been at war with Russia since the latter invaded in February of that year. Ukraine denied involvement, and in the absence of reliable information, conspiracy theories proliferated about who attacked the Nord Stream pipeline.

Did a Russian submarine intentionally destroy it in order to cut off the gas supply to Germany, a country allied with Ukraine? Was it the CIA, as famed U.S. investigative journalist Seymour Hersh wrote? 

The German government has been tightlipped about the affair for two years, but this week, German media outlets ARD, Sueddeutsche Zeitung and Die Zeit jointly reported that federal prosecutors obtained an arrest warrant against a Ukrainian man. A Polish government spokesperson confirmed it. 

The German reports identified the man as Volodymyr Z., a diving instructor who last resided in Poland. In a brief telephone conversation on Tuesday with reporters from ARD, Sueddeutsche Zeitung and Die Zeit, Volodymyr Z. expressed surprise at the accusations and denied involvement.

A report this week by the Wall Street Journal also pointed to Ukraine, suggesting the operation was carried out by Ukrainian soldiers and civilians with diving expertise and under the direction of Ukraine's then-commander-in-chief, Valerii Zaluzhnyi.

Journalists at ARD, Germany's public broadcaster, have been hot on the trail since the shocking explosions took place. I was one of the reporters who was part of the team that spent months piecing together what may have occurred. 

To understand what happened to the Nord Stream pipeline that day, ARD chartered the very yacht the perpetrators allegedly used and sent divers into the roiling waters of the Baltic Sea to see how the pipeline might have been attacked.

Several outlets have reported that in early September 2022, a sailing yacht called Andromeda set sail from the port of Hohe Düne in Rostock, Germany. According to the ARD investigation, the commando that was to destroy the pipelines was on board the Andromeda. The group is said to have consisted of six people — five men and one woman. Among them, it is suspected, was Volodymyr Z.

After stops in Rügen, Bornholm and Christiansø in Denmark, Sandhamn in Sweden and Kołobrzeg in Poland, the boat returned to Rostock. 

At some point during the trip, investigators believe the crew dove from the yacht down to the seabed and, in the darkness of the Baltic Sea, attached the explosive devices to the pipeline at a depth of around 80 metres. 

What happened later is well-known. At 2:03 a.m. local time on Sept. 26, 2022, the first explosion damaged Nord Stream 2. Approximately 16 hours later, three other explosions damaged Nord Stream 1. Investigators later found residue of the explosive HMX, also known as octogen, on board the Andromeda.

During our investigation, we wondered just how hard it would have been to carry out such a mission.