He was notorious for publishing an autobiography titled
Don Juan of Kishu: The Man Who Gave 3 Billion Yen to 4000 Beautiful Women in 2016. Three billion yen is £19.7m.
Nozaki was found dead at his home in Wakayama Prefecture, Tokyo, and found traces of an illegal stimulant drug in his body but no needle marks, leading them to believe it was a case of poisoning.
Police have also said Ms Sudo was alone with Nozaki before his death and had also ruled out suicide.
Soon after his death, the Nozaki murder case gained widespread attention.
The local government had earlier said Nozaki had mentioned in his will that he would donate all of his property, worth around 1.3 billion yen (£8.6m), to the city.