GUATEMALA CITY –  A businessman who served as private secretary to former President Alvaro Colom turned himself in to authorities Monday to faces charges related to a kickback scheme in government medicine purchases.

Gustavo Alejos Cambara, who was accompanied by his lawyers when he surrendered, had worked for Colom during his 2008-2012 presidency.

Alejos Cambara is alleged to have profited from irregular purchases of medicine for government hospitals. Just before a hearing on whether he would be jailed pending trial, he told local media he was innocent of any wrongdoing.

The judge ordered him held overnight and said the session to hear his case would resume Tuesday.

Prosecutors detained 11 other people in October connection with the scheme, in which medicine sellers plotted with buyers at hospitals to fix prices in bidding processes and offer kickbacks or favors in return for contracts.

The investigation was conducted with a U.N. commission set up to tackle criminal networks and impunity in Guatemala.