Kenya's President Uhuru Kenyatta has called for answers after an audit last week found that a third of the country's public spending could not be accounted for. Earlier in May, members of parliament voted themselves a $120 thousand annual salary, making them among the highest paid in the world. After a public outcry, they eventually agreed to cut that to $75 thousand. Now, $4bn cannot be accounted for at a time when Kenya is trying to raise funds by introducing a sales tax. Al Jazeera's Peter Greste has more from Nairobi.