"Lotti", the suspected alligator snapping turtle of the Oggenrieder Weiher

The Oggenrieder Weiher is a natural bathing lake on the edge of Irsee, in the Ostallgäu district of Bavaria. It is small. 1.4 hectares. In the summer of 2013 it became the scene of a hunt for an animal nobody had ever seen.

Monday, 5 August 2013. An eight-year-old boy on holiday with his family from Bonn was swimming in the shallows. Medics first thought he had stepped on glass. But the bleeding and the pain pointed to something worse. His Achilles tendon had been cut twice, and the wounds were hook-shaped.

The surgeon read it as an animal bite. Mayor Andreas Lieb sent photographs of the wound to the Zoological Institute in Munich. The answer came back: a turtle. No fish in the lake, the experts said, could have done it. The suspect was an alligator snapping turtle, about 14 kg and 40 cm across, able to burrow up to 2 m into the mud, and locals and reporters called her Lotti.

On the evening of Sunday 11 August, the Fischereiverein Kaufbeuren moved about 500 fish and the fire brigade drained the lake. Electric fences went up, sniffer dogs came, then an RTL drone. Eight zoologists from Munich joined 15 volunteer firefighters, probing the mud with long reed poles. The town offered a €1,000 reward. Local girls hung laminated posters by the water: "Beware, Lotti lives here."

Lieb called such turtles "masters of disguise," and the village blacksmith, Hans Kohlhund, 75, built a metre-wide wrought-iron rake. "We'll get her out of the sludge with a giant rake," Lieb told Bild. The rake found nothing, and boats and night cameras failed too. Traps were ordered from America, and in October floating live traps were baited with whitefish and beef rumen. "This is our last chance before winter," Lieb said.

Not Lotti. A 20 cm crayfish surfaced during the draining. An anonymous caller said their own alligator turtle had escaped about two years earlier. In June 2014 a resident saw a duck disappear at a silting pond on the western edge of Irsee. The town fenced the pond and set a turtle trap, but no capture was ever reported.

Doubt was there from the start. Markus Baur, head of the Munich reptile rescue centre, was on site. "No one in the world can say for certain that it was a turtle," he said. Lieb drew his own comparison: "At Loch Ness there were only sightings. But we unfortunately have someone seriously injured."

In June 2014 the website Aqualog made the sceptics' case. Nobody saw the animal, and there was not a single documented case of such an injury from a snapper. An alligator snapper would leave a ring of grooves around the ankle, and could not sever a tendon. "Whatever actually caused his injury (probably a piece of glass or wire), it certainly wasn't Lotti." Aqualog even asked whether Lotti was a PR stunt.

Others filed the affair under Sommerloch, the silly season. If there was a turtle, it was most likely an escaped or released pet.

By 2014 the boy was doing fine. Lotti never surfaced. Irsee kept her anyway. There is a song, a Facebook page and a turtle-shaped pretzel roll from the Koneberg bakery. In July 2021 the town unveiled a steel sculpture of Lotti by the Irsee metal sculptors Peter Müller and Roman Reitzer.