Prosecutors last week referred to court the case of Bassem Awadallah, an ex-royal court chief and finance minister who played a big role in the drive to liberalize Jordan's economy, and Sherif Hassan Zaid, a distant relative of King Abdullah.
They were arrested in early April when former heir to the throne Prince Hamza was placed under house arrest over allegations that he had liaised with foreign parties over a plot to destabilize Jordan, a close US ally in the Middle East.
Proceedings against Prince Hamza, who along with Awadallah had been under investigation for some time, were later dropped after he pledged allegiance to King Abdullah.
Awadallah is among the closest economic advisers to Saudi Arabia's de facto ruler, Crown Prince Mohammed bin Salman, a matter that complicated the judicial investigations, two senior politicians familiar with the affair told Reuters on condition of anonymity.
Amman turned down Riyadh's request to hand him over, they added, without elaborating.
The intrigue exposed the first serious rift within Jordan's ruling Hashemite family in many years and shook the image of the country as an island of stability in an unpredictable region.