A Swiss exchange student who recently qualified as a diving instructor heroically fought off a bull shark mauling his girlfriend before carrying her to shore, and raised the alarm after being bitten twice on the leg himself.

Lukas Schindler, 26, and his 25-year-old girlfriend Livia Mühlheim, also a Swiss national, were swimming near the remote Kylies Beach campground, about four hours north of Sydney, when what authorities believe was a mature bull shark at least three metres long attacked them just after 6am on Thursday.

Mühlheim was attacked moments after her GoPro captured her swimming with dolphins. She was bitten several times and lost her left arm in the fatal attack.

Schindler, who according to his LinkedIn profile completed an exchange semester at the University of Technology Sydney from July to November this year, swam out to his girlfriend and was bitten twice on the right leg while trying to punch the shark.

In August, he ran the Sydney Marathon in a time of two hours and 59 minutes, according to the race’s official results website.

Despite his injuries, Schindler swam his girlfriend back to shore, retrieved his phone and ran up the beach to call emergency services. His life was most likely saved by a passerby, praised by authorities for their quick thinking, who applied a makeshift tourniquet to his injured leg. Mühlheim died on the beach.

Schindler was flown to Newcastle’s John Hunter Hospital, where he remained in a stable condition on Friday.

Police are reviewing the couple’s GoPro footage, which captured dolphins in the water moments before the attack. It is unclear if the attack was captured on camera. A report will be prepared for the coroner.

Mühlheim had worked as an investment associate at Bellecapital, an asset and wealth management firm based in Zurich and London, since last May, when she was hired as a junior associate, according to her LinkedIn profile.

She graduated from Switzerland’s University of St Gallen with a bachelor of arts in 2023, and was studying a master’s degree in accounting and corporate finance, according to the profile.

Bellecapital declined to comment on Mühlheim’s death when contacted by the Herald.

Mühlheim was an accomplished synchronised swimmer, according to Swiss news articles and her employer.

Schindler completed a diving instructors’ course at a Bondi dive centre, according to an online review posted last week.

He completed a bachelor of business administration at the University of St Gallen, Switzerland, in 2024 and was studying a master’s degree in general management, according to his LinkedIn profile.

According to the profile, Schindler has worked as a security supervisor at the World Economic Forum and was a first lieutenant in the Swiss Armed Forces.

Campers said Schindler and Mühlheim arrived at the Mid North Coast campsite late on Wednesday night and set out for an early morning swim at the unpatrolled beach at first light on Thursday.

Drum lines and drones were on Thursday deployed to track down the shark believed to have attacked the couple.

Thursday’s attack came less than three months after a shark fatally attacked 57-year-old surfer Mercury Psillakis at Dee Why on Sydney’s northern beaches in September. His widow, Maria Psillakis, has called for an overhaul of alert systems at Sydney beaches.

Shark receivers, which ping when a tagged animal swims within 500 metres, are in place at 37 beaches along the NSW coast between Tweed Heads and Bega. There is no receiver at Kylies Beach, with the closest located at Old Bar, about 30 kilometres south.

Police on Thursday contacted the consulate general of Switzerland in Sydney and the couple’s family abroad. The Herald has made attempts to contact the couple’s family.

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