Police raided a public hospital in the city of Kyoto Tuesday in relation to the alleged helping of a senior member of a crime syndicate stay out of prison by the forging of a certificate of illness.

A doctor at the Kyoto Prefectural University of Medicine hospital is suspected of falsifying a certificate for Yoshiyuki Takayama, the 60-year-old head of a yakuza group under the western-Japan-based Yamaguchi-gumi, investigative sources said.

Takayama was arrested in April 2010 on extortion charges but released on bail for health reasons in May 2012. He was sentenced to eight years in prison for crimes including extortion in June 2013, a sentence finalized by the Supreme Court in 2015. But citing a kidney disease, he has avoided imprisonment.