Ogata was born in Kurume, Fukuoka Prefecture, and grew up in a wealthy family.
She was originally a gentle person and got a job in a preschool, but changed after she started dating Matsunaga in 1982.
Ogata had remained a virgin until she became involved with Matsunaga, but he suspected her of having relationships with other men.
Japanese writer Masayoshi Toyoda supported her, and created doubt about the trial in his book published in November 2005.
On September 26, 2007, the high court in Fukuoka sentenced her to life in prison, rejecting the death penalty.