The Woman Who Took the Local Paper (1973)

Based on the original mystery novel by Seicho Matsumoto.
Novelist Ryuji Sugimoto is publishing his serial in a local newspaper when a woman from Tokyo subscribes, saying she’s interested in his work—only to abruptly cancel weeks later. Suspicious, he realizes her true interest may not be the fiction at all, but a real double suicide reported in the same paper.