Nagasaki Prefectural Police are investigating the killing of Chiaki Nonoka, 28, after a resident reported that she was unconscious in the car parked on a street in the town of Sankeidai.
Nonoka, who died three hours later at a hospital, was sitting in the driver’s seat with a stab wound to the head. A knife was also found in the car.
Police later found a man, believed to be Nonaka’s former husband, hanged inside a residence near the vehicle. He was later confirmed dead at a nearby hospital in what is being seen as a suicide.
Police are now seeking to question a male relative of the man about the case.
Nonoka consulted with the Isahaya Police Station regarding a stalker in November 2016.
Officers regularly kept in touch with Nonoka by meeting with her and calling her, and there was nothing irregular when she was contacted earlier this month, police said.