The head, thought to belong to the woman, was discovered in a suitcase left behind at a lodging facility in Osaka’s Nishinari Ward.
Police investigating the woman’s disappearance from Hyogo Prefecture announced that officers had made the gruesome find on Saturday.
The American man, aged 26, was previously arrested in Nara Prefecture on Thursday on suspicion of confining the missing woman in a holiday flat in Osaka’s Higashinari Ward, sources told the Japan Times.
The case is being treated as abandonment of a corpse, the report added.
Before the woman vanished, she had written on Instagram that she was going to meet a man named “Jay”.
Police set up a special investigative unit to probe the disappearance of the woman, from Sanda.
Investigators have said that CCTV shows the woman and a man walking towards the apartment block on February 16, and then entering the suspect’s holiday flat.
The cameras did not capture the woman leaving the building, they added.
The woman’s mother reported her missing the following day, telling police that she was unable to contact her.
(Mirror)