Prosecutors on Tuesday raided the Tokyo head office of Tokushukai hospitals and medical facilities on suspicion its employees were illegally involved in December’s general election campaign of Liberal Democratic Party Lower House member Takeshi Tokuda.

Tokuda, 42, a third-term House of Representatives lawmaker from Kagoshima Prefecture’s No. 2 constituency, is the second son of Torao Tokuda, 75, founder of the Tokushukai group and a former Lower House member.

More than 200 employees of the Tokushukai group allegedly joined Tokuda’s election campaign after the Diet’s lower chamber was dissolved last Nov. 16 and worked on his general election campaign until Dec. 15, the day before the poll, investigative sources said.

While the employees took unpaid leave to work on the campaign, the Tokushukai group is believed to have increased their bonuses to make up the shortfall in income, a practice deemed corrupt under the Public Office Election Law, the sources said.

The Tokyo District Public Prosecutor’s Office will investigate whether Tokuda and his father were involved and, if so, to what extent, the sources said.

Initially elected to the Lower House in 2005, Tokuda was appointed last December as parliamentary secretary in charge of infrastructure and transport as well as Tohoku’s reconstruction from the March 2011 triple disaster. However, he resigned in February after a scandal broke out over his relationship with a woman.