Kenyan authorities arrested the head of a government agency on Monday in a corruption investigation into the theft of nearly $100 million, a rare move to hold officials to account for graft in a nation where it is widespread.

President Uhuru Kenyatta‘s pledged to stamp out graft when he was first elected in 2013, but critics say he has been slow to pursue top officials.

A government SUV brought Richard Ndubai, director general of the National Youth Service, and several unidentified people, to a police station in the Nairobi neighbourhood of Muthaiga at midday on Monday, a Reuters witness said.

All those under arrest had their heads covered with hoods, the witness said.

Reuters could not contact Ndubai, who is in custody, for comment, and was unable to immediately contact his lawyer.

After more than a week of front-page stories in Kenyan newspapers and numerous hashtags on Twitter, the prosecutor’s office said on Twitter that prosecution would begin of all suspects named in a file by the police’s criminal investigations department. Most of those names have not been made public yet.

The director of public prosecutions, Noordin Mohamed, told Reuters last week that his office was investigating pending bills totalling at least 8 billion shillings ($99 million).Kenyan media reported the funds were stolen through fictitious invoices and multiple payments on one supplier invoice.

The director of criminal investigations, George Kinoti, told Reuters that a total of 17 people had been arrested and would be charged tomorrow.

The case – first reported earlier this month by the newspaper Daily Nation — has touched a nerve, particularly on social media, where some Kenyans are mocking the Kenyatta administration for lip service on corruption.

Government critics say only big-name convictions will break what they call a culture of impunity. There have been none on Kenyatta’s watch, they say.

Many Kenyans say they believe that the amount allegedly looted by youth service officials is a fraction of the overall amount of money stolen annually by government officials.

The state organisation trains young people and deploys them to projects ranging from construction to traffic control.

The current scandal follows one three years ago at the same agency. Earlier this year, a court acquitted nearly two dozen officials at the agency after a trial over the alleged theft of48 million shillings in 2015.

In 2016, the then-head of Kenya’s anti-graft agency said Kenya was losing a third of its state budget – the equivalent of about $6 billion – to corruption every year.

While the finance ministry disputed the losses were that large and instead blamed poor paperwork, Kenyatta acknowledged then that corruption had reached levels that threatened national security.