Police started an investigation Monday after a woman's corpse was found in a Miyagi Prefecture park dedicated to victims of the 2011 Great East Japan Earthquake and tsunami.

An autopsy determined that the woman sustained a broken thighbone and ribs, indicating the cause of death may have been multiple blunt-force trauma, and that she had been dead for about a week.

According to investigators, a resident who was walking his dog found the woman lying on her back in the southern part of a park, located in the Sennen Kibo no Oka (Millennium Hope Hills) memorial area, at around 6 a.m. Sunday. He called the police soon after.

The woman, who was said to be somewhere between her 40s and 60s, was 165 cm tall and had shoulder-length black hair. She was wearing a long-sleeved dress.

Police said the woman may have lived in Miyagi Prefecture based on a driver's license found in a tote bag on the ground near the body.

The park's hills, made from debris from the quake and tsunami, are about 10 meters high. People occasionally visit the park to offer prayers for the victims of the disaster.

The park was also built to serve as an evacuation area in case of tsunami, and to hand down the experience of the 2011 disaster.

There are usually few people in the park, which is located where homes and commercial facilities were wiped out by the tsunami.