Nigerian President Muhammadu Buhari suspended two senior administration officials linked to graft allegations and ordered an investigation, the presidency said.

David Lawal, secretary to the government, is being probed for alleged violations of “law and due process” in the award of contracts, presidential spokesman Femi Adesina said Wednesday in an emailed statement.

Ayo Oke, head of the National Intelligence Agency, is facing investigation over the discovery of $38 million and other currencies in cash said to belong to the agency in a private residence.

A committee including the attorney-general, the national security adviser and the vice president will carry out the investigations and report to Buhari within 14 days, Adesina said.

Bolaji Adebiyi, a spokesman for Lawal, wasn’t immediately available for comment. The National Intelligence Agency couldn’t be reached for comment.

Buhari, 74, came to power in 2015 promising to curb corruption, and the anti-graft agency recovered $160 million in allegedly illicit proceeds in February.

Nigeria is ranked 136 out of 176 countries on Berlin-based Transparency International’s 2016 Corruption Perceptions Index.