Janine Lochrenberg was an experienced ocean swimmer.

She was also wearing a shark-repellent band when a shark fatally attacked her off South Africa. That detail is raising painful questions about the devices marketed to protect people in the water.

The 65-year-old retired medical physicist was swimming with her open-water group Tuesday morning, October 20, off Orient Beach in KuGompo, formerly East London. Witnesses said she screamed after suffering severe bites to her thigh and upper arm. Fellow swimmers dragged her toward shore and tried CPR, but she could not be revived.

Rest in peace, Janine Lochrenberg, the 65-year-old swimmer who died following a fatal shark attack in South Africa. Facebook/Avril Jason

“We were all in the water, swimming. We were wearing [magnetic shark repellents] on our feet. She had one on,” fellow swimmer Mike Loewe told News24, as quoted by PEOPLE .

Lochrenberg’s sister, Margot, helped hold her head during the desperate rescue.…