Nobuhisa Sagawa, a former National Tax Agency head, bows prior to testifying before an upper house panel at the parliament in Tokyo Tuesday, March 27, 2018. Sagawa testified over a questionable school land deal linked to Prime Minister Shinzo Abe's wife Akie Abe, in a widening scandal that has sent his support ratings plunging. AP Photo/Eugene Hoshiko

Nobuhisa Sagawa, left, a former National Tax Agency head, raises his hand to testify before an upper house panel at the parliament in Tokyo Tuesday, March 27, 2018. Japan's Prime Minister Shinzo Abe, his wife, Finance Minister Taro Aso and their top aides did not give instructions to change documents about a land deal at the heart of a suspected cronyism scandal, a former finance ministry official said on Tuesday. AP Photo/Eugene Hoshiko

Former Japanese tax agency chief Nobuhisa Sagawa, a key figure in a cronyism scandal that has sparked a political crisis for Prime Minister Shinzo Abe, arrives to testify at the Upper House of the parliament in Tokyo, Japan March 27, 2018. Sagawa, formerly head of the finance ministry division in charge of the documents, was testifying in parliament under oath. Sagawa declined to comment on motives for altering the documents because he is a subject of investigations into the matter. REUTERS/Toru Hanai

Former Japanese tax agency chief Nobuhisa Sagawa, a key figure in a cronyism scandal that has sparked a political crisis for Prime Minister Shinzo Abe, takes oath to tell the truth as he testifies at the upper house of parliament in Tokyo, Japan March 27, 2018. The suspected scandal and possible cover-up have slashed Abe's ratings and clouded his chances of a third three-year term as ruling Liberal Democratic Party (LDP) leader in a September party vote. REUTERS/Toru Hanai

Former Japanese tax agency chief Nobuhisa Sagawa, a key figure in a cronyism scandal that has sparked a political crisis for Prime Minister Shinzo Abe, answers a question as he testifies at the upper house of parliament in Tokyo, Japan March 27, 2018. The finance ministry admitted on March 12 that it had altered documents about a heavily discounted sale of state-owned land to school operator Moritomo Gakuen, which had ties to Abe's wife, Akie. REUTERS/Toru Hanai

Former Japanese tax agency chief Nobuhisa Sagawa, a key figure in a cronyism scandal that has sparked a political crisis for Prime Minister Shinzo Abe, takes an oath to tell the truth as he testifies at the upper house of the parliament in Tokyo, Japan March 27, 2018. But Sagawa, who resigned as National Tax Agency chief this month, said that he did not think that Abe or his wife influenced the land sale itself. Abe has repeatedly denied that he or his wife intervened in the sale or that he ordered a cover-up but public doubts have persisted. REUTERS/Toru Hanai