MISAWA, Japan — Police here said Monday they’re continuing to investigate the death of a local Japanese woman found July 21 in Hachinohe, but they refused to release how she died.

“An autopsy has been performed and the cause of death has been determined. However, the information is not for the public,” a spokesman for Aomori prefectural police in Misawa said Monday. He added, however, that “police are investigating the case as murder and abandoning of a dead body.”

Naomi Kimura’s body was found in the trunk of her burning vehicle on railroad tracks in Hachinohe, about 15 miles south of Misawa. The 33-year-old mother also owned or co-owned the Purple Haze bar in downtown Misawa.

As of Monday, no arrests had been made in connection with Kimura’s death, the police spokesman said.

“Voluntary questioning of the people concerned is under way,” he said. Asked if those individuals included status of forces agreement personnel, the spokesman refused to answer the question.

Last week the Air Force Office of Special Investigations at Misawa announced that, at the behest of Japanese police, they were asking anyone with information about the case to come forward. Agents have so far deferred any questions about the case to Misawa police.

The Misawa police spokesman refused to verify a media report that it appeared someone poured copious amounts of oil around Kimura’s car trunk before setting the vehicle on fire.

“Police, however, believe that the victim had been killed before she was put in the trunk,” he said.