Ichung'wah's accusations follow a myriad of attacks by the former DP on the Kenya Kwanza government.
The multibillion-shilling project is set to kickstart next month.
The government recently revealed a timeline on when it intends to break ground at the JKIA.
Mutua has been ordered to repay the millions as fast as possible.
Gachagua addressed the media on Wednesday afternoon, hitting back at the President.
The deal comes to light barely a month after the government promised to cut rice imports.
The government is facing pressure to recruit more teachers, with mooted plans to hire at least 16,000 before January next year.
The chaos left businesses counting losses, with over 30 people dead.
He has been in and out of court since 2021.
The changes come amid uproar from teachers over promotions announced in June.