After three days of being lost, a woman is rescued thanks to her SOS message in the sand

(CNN)An Australian woman has a surveillance camera to thank for her rescue after she got lost while camping with friends.

Deborah Pilgrim, 55, didn't return from a walk Sunday in Sedan, about 60 miles from Adelaide.
Police searched for three days. They used a chopper, drones, volunteers and several other adjacent agencies -- without success.
"We held great fears for her safety," the South Australia Police said in news conference. "That area is quite harsh...very easy to lose your footing.
"Of course, with venomous reptiles around the place, if she had been snake struck, she would have been in all sorts of grief."
    Before the fourth day of search and rescue, the police received some information from a man who has property in the area.
    The man owns a block of the wilderness and has a surveillance camera on his property.
    Because he knew authorities were looking for Pilgrim, he had been checking the footage more frequently.
    On Wednesday, he noticed the letters S-O-S in a part of his property.
      He notified police who found Pilgrim safe and sound in a shack where she had access to water.
      She appeared in good health, but was taken to the hospital as a precaution, police said. She has since been released and is back home.