An amateur mountaineer has been found guilty of gross negligence manslaughter over the death of his girlfriend, whom he left behind on Austria’s highest peak after they got into difficulty on their climb.

Thomas P, 37, was handed a five-month suspended sentence and fined €9,400 (£8,200) for causing the death of Kerstin G in January 2025 by gross negligence, an offence that carries a maximum prison term of three years.

The lengthy one-day hearing at a court in Innsbruck, western Austria, drew worldwide attention from the mountaineering community in an extremely rare case of a prosecution over a climbing incident.

Experts say the ruling sets a precedent that could influence international standards for liability in mountain sports.

Thomas P, a chef from Salzburg, had pleaded not guilty and told the court he was “endlessly sorry” for his girlfriend’s death. His lawyer described the death of the 33-year-old woman as a “tragic accident”.

The court heard that after a gruelling day of climbing in freezing conditions in January 2025 , during which the pair had fallen well behind schedule, Kerstin G was exhausted, suffering from hypothermia and lacked the strength to continue. They were about 50 metres below the summit of the Großglockner mountain when night fell.

Thomas P said the situation had been “very stressful”.

He said he had left Kerstin G on a ridge exposed to strong winds when he went to seek help. He told the court he could not explain why he had failed to wrap her in the emergency blanket she was carrying or place her in a bivouac bag. When her body was later recovered, the items were found in her rucksack.

Giving evidence, a police officer on duty that night, who had called Thomas P on his mobile at 12.35am, after a helicopter had set off to monitor the couple two hours earlier amid concerns for their safety, said the defendant had told him: “We don’t need anything … everything’s fine”.

The officer had advised Thomas P that the couple should keep moving. The discussion had ended abruptly. The officer attempted to call him twice more, and to find out if the pair needed help, and sent text messages, but had received no reply. Later, conditions became too dangerous for the helicopter to attempt a rescue.

The prosecutor, Johann Frischmann, accused the defendant of failing to live up to his “de facto” role as leader of the tour, due to him being the more experienced climber.

One expert witness referred to the defendant’s social media posts, including details of his previous feats, as one of the pieces of evidence that Thomas P was a better mountaineer than his girlfriend.

The mistakes made, the court heard, included failing to recognise that Kerstin G was wearing the wrong type of footwear for the terrain, neglecting to adequately take into account the weather conditions for that time of year, and failing to turn back earlier given the conditions.

Prosecutors based key parts of their accusations on an expert report, which analysed the data from both climbers’ smart watches, which documented a clear decline in their physical performances. This was evident even before the police helicopter had flown over at about 10pm. The defendant had failed to call emergency services in time and reacted too late to rescue attempts, they said.

The court was filled with journalists, local people and representatives of mountain emergency response organisations from Austria and elsewhere in Europe.

A former girlfriend, called as a witness, testified that she had also climbed the Großglockner with Thomas P in 2023. She said he had abandoned her on the route at night after her head torch ran out of battery, leaving her distressed. “So that was the last mountain expedition we undertook together,” she said.

The court was shown webcam footage of Thomas P and Kerstin G ascending the mountain, as well as Thomas P descending alone. The beam of his torch lit up bright against the snowy mountainside.