"Preliminary findings indicate marks of violence on the body. All avenues are being explored," the police said in a statement yesterday.
Police said the woman's body was found by walkers in a forest two kilometres (just over a mile) south of Nazareth, the country's largest Arab Israeli town and a place of pilgrimage for Christians.
She and her father had been staying with a group of Polish tourists in a Nazareth hotel, and had been reported missing on Thursday, police said.