TOKYO, Nov 12 (AFP) - Japanese police planned to deploy up to 500 officers Friday to scour a mountainous area for more remains of a woman whose head and other dispersed body parts have been found since last week.

A mushroom collector last Friday discovered the severed head of 19-year-old college student Miyako Hiraoka, who went missing last month after leaving work at an ice cream parlour in Shimane prefecture.

Police, deploying about 200 officers a day so far, have since found her torso, left ankle and a thigh bone, all in separate locations and possibly hurled into the undergrowth from a vehicle.

"This is a tough case," a local police spokesman told AFP. "We have widened the investigation to local rental video shops because the perpetrator may be some psychopath who likes horror movies."

Media have reported that the head showed signs of assault before her death, that both breasts had been cut off the torso, which also bore burn marks, and that the flesh seemed to have been scraped off the thigh bone.

Hiraoka went missing in the evening of October 26 after she left an ice cream shop at a shopping mall where she worked part-time.

She had complained of having to walk home along dark and deserted mountain roads and had planned to quit her job within days, media reports said.