BRASILIA (Reuters) - Brazil’s Federal Police have nearly doubled the number of agents assigned to investigate sitting politicians suspected of corruption in the nation’s largest graft scandal ever, a person with direct knowledge of the matter said on Thursday.

The Federal Police have increased to 17 from nine the number of agents dedicated to investigating sitting politicians in the “Operation Car Wash” probe, the source told Reuters.

The number of agents and other staff working on the cases on a contingency basis will also be increased.

The source said additional staffing is to speed up the cases after public criticism that President Michel Temer, who is himself accused of corruption, could use his recent appointment of the new head of the Federal Police to impede the investigation.