Hiroshi Nakatsuka KYODO PHOTO

Osaka prosecutors arrested the mayor of Hirakata, Osaka Prefecture, on July 31 on suspicion of involvement in bid rigging in 2005 for a garbage incinerator plant construction project.

Hiroshi Nakatsuka, 51, is suspected of favoring a joint venture of Obayashi Corp. and Asanuma Corp. in bidding for the project in November 2005, in conspiracy with several others, according to the prosecutors.

Nakatsuka has repeatedly denied the allegations at news conferences and in the city assembly.