The suspect spy was a vulture.
Really, I mean that literally.
It appears that an Israeli academic tagged some vultures with tracking tags, and the Saudis were worried about their potential threat to state security:
A Saudi Arabian prince has announced that a tagged Israeli vulture captured last week and accused of being a Mossad agent will be released, according to ABC News.
The bird was reportedly captured last week by Saudi officials and accused by local media of being part of a “Zionist plot” after it was discovered wearing a GPS tracker labeled Tel Aviv University.
Prince Bandar bin Saud Al Saud dismissed the accusations on Sunday: “These systems are fitted to birds and animals, including marine animals. Most countries use these system, including Saudi Arabia. We have taken delivery of this bird, but we will set it free again after we [have] verified its systems.”
When a member of the House of Saud is the voice of sanity, you are doing something very wrong.