Prosecutors are set to search sites this weekend linked to the nationalist school operator at the center of a scandal tied to Prime Minister Shinzo Abe and his wife, for evidence of fraud related to subsidies for its preschool, investigative sources said Friday.

The criminal investigation into Yasunori Kagoike, 64, would come some four months after the school operator, Moritomo Gakuen, was found to have received a hefty ¥800 million ($72,800) discount on state-owned land in Osaka. The revelations fueled scrutiny of Abe and his wife, Akie, who was named honorary principal of an elementary school Kagoike planned to open on the land, and even went there to give a speech promoting Moritomo Gakuen.

In May, the prosecutors received a criminal complaint alleging that Tsukamoto Kindergarten in Osaka, run by Moritomo Gakuen, had swindled some ¥62 million in subsidies from the Osaka Prefectural Government.