A woman is in serious condition after she was attacked Sunday by a crocodile at a popular lagoon near Puerto Escondido, Oaxaca.

Melissa Laurie, 28, and her twin sister Georgia were on a night tour to view the bioluminescence at Manialtepec Lagoon when they went into the water for a swim, the British newspaper the Daily Mail reported on Monday.

But Melissa Laurie was snatched by a crocodile and dragged beneath the surface. After searching frantically for several minutes, Georgia found her sister floating face down in the water. But as she cradled her sister in her arms and began to swim back to the boat, the crocodile attacked again.

Georgia fought it off, punching the reptile until it let go, the newspaper reported.

On Monday, local media reported that Melissa Laurie was in serious condition in a private hospital in Puerto Escondido, but her sister was reported stable.

Their mother, Sue Laurie of Berkshire, England, told the Mail that Melissa had been put into a medically-induced coma. “Melissa is alive, but we don’t know if her injuries are life-threatening or not.” She said both had suffered terrible bite injuries.

Sean Laurie, the girls’ father, said Georgia was able to save her sister because she is a diver and has lifesaving experience.

He also said they had asked their tour guide if it was to safe to swim, and were assured that it was. Going for a dip in the lagoon is common and indeed, tour guides invite visitors to enjoy the bioluminescence from within the water.

The two young women are in the midst of a backpacking tour around the world. They left the U.K. in March and had planned to return home in November.

With reports from the Daily Mail