It was an event that shook Europe and world events.

In the early morning of September 26, 2022, a series of violent underwater explosions damaged pipelines under the Baltic Sea near Denmark that carried Russian natural gas to Germany.

The finger was immediately pointed at Ukraine, which had been at war with Russia since the Russian invasion in February of that year. Ukraine denied any involvement and, in the absence of reliable information, conspiracy theories circulated about who had attacked the Nord Stream pipeline.

Did a Russian submarine deliberately destroy the bomb in order to cut off the gas supply to Germany, an ally of Ukraine? Was it the CIA, as the famous US investigative journalist Seymour Hersh wrote?

The German government has remained silent on the affair for two years, but this week German media ARD, Süddeutsche Zeitung and Die Zeit jointly reported that the Federal Prosecutor’s Office had obtained an arrest warrant for a Ukrainian. A Polish government spokesman confirmed this.

In the German reports, the man was identified as Wolodymyr Z., a diving instructor who had last lived in Poland. In a brief phone call on Tuesday with reporters from ARD, Süddeutsche Zeitung and Die Zeit, Wolodymyr Z. expressed surprise at the allegations and denied being involved in the allegations.

A Wall Street Journal report this week also pointed to Ukraine, suggesting that the operation was carried out by Ukrainian soldiers and civilians with diving experience and under the leadership of Ukraine’s then-commander-in-chief, Valery Zalushny.

ARD journalists have been on the trail of events since the shocking explosions. I was one of the reporters who was part of the team that spent months reconstructing the events.

To understand what had happened to the Nord Stream pipeline that day, ARD chartered the very yacht that the perpetrators were alleged to have used and sent divers into the turbulent waters of the Baltic Sea to find out how the pipeline might have been attacked.

Sailing yacht chartered for groups

Several media outlets reported that in early September 2022, a sailing yacht named Andromeda set sail from the Hohe Düne harbor in Rostock. According to research by ARD, the commando that was supposed 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 stopovers in Rügen, Bornholm and Christiansø in Denmark, Sandhamn in Sweden and Kołobrzeg in Poland, the ship returned to Rostock.

At some point during the voyage, investigators assume, the crew dived from the yacht to the seabed and attached the explosives to the pipeline in the darkness of the Baltic Sea at a depth of around 80 meters.

What happened later is known. On September 26, 2022 at 2:03 a.m. local time, the first explosion damaged Nord Stream 2. Around 16 hours later, three more explosions damaged Nord Stream 1. Investigators later found residues of the explosive HMX, also known as octogen, on board the Andromeda.

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

The Andromeda is a charter yacht. Anyone can rent it – so we rented it and took three divers with us.

Like many charter yachts, the Andromeda was not in the best condition – our skipper called it “one of the worst boats I have ever sailed.”

He said that several electrical components were broken and that the yacht did not move well in the waves. Then there was the bathing platform that the divers use to get on and off the boat. In high waves, the platform moves up and down and hits the sea. A diver trying to get back on the boat could be hit in the head by the platform and suffer serious injuries. For us, this risk was too high.

So we returned the Andromeda and chartered a professional diving vessel with a crew that normally recovers World War II explosives from the bottom of the Baltic Sea.

We then drove to the exact spot where the first explosion had occurred – 120 kilometres off the German coast, with the Danish island of Bornholm in sight.

Trained divers required

We arrived at 6am to witness a symbolic moment in the Baltic Sea.

A Russian warship appeared. We heard over our radio: “Russian warship Delta Echo, US warship Yankee.” The US Navy was trying to make contact with the Russian Navy right before our eyes. How could a sabotage operation go undetected in this environment?

The burst pipeline lay almost 80 meters below us, a depth that not every diver can manage.

You must be trained as a technical diver. At this depth you must breathe a special mixture of oxygen, helium and nitrogen and this means you must carry around 100 kg of equipment.

It is also pitch black on the sea floor. The divers had about 40 minutes to find the pipeline thanks to the numerous diving tanks. They therefore had to know exactly where to look. A sonar device was needed to locate the pipeline in advance. The Andromeda did not have such a device on board, but our new ship did.

Our technical divers found and filmed the burst pipeline on the second attempt.

The most difficult part for the divers was returning to the surface. The pressure is so high that an improper ascent can result in severe symptoms such as paralysis or lung damage. Proper decompression from such a depth – which requires divers to switch to a different gas mixture – takes about two hours.

Carrying out such a complex mission from the Andromeda would have been difficult and dangerous. According to the German investigations, it is plausible that Volodymyr Z. was trained for such dives.

Everyone who has studied the Andromeda agrees that it is not the ship anyone would choose to carry out a mission.

Our technical diver Derk Remmers put it this way: “I would use the Andromeda for a vacation, but not for a sabotage mission.”

But that is precisely why the saboteurs may have used this method: to remain undetected and unaccountable – which they managed to do until the allegations became public this week.