Last month Saudi Arabia extradited an Islamic terrorist to India, and this was the third such extradition this year. Partly, this is the result of Indian intelligence officials showing their Saudi counterparts the huge amount of intel India had on Indian Islamic terrorists getting training, direction, and financing from terrorist leaders enjoying sanctuary in Saudi Arabia. A more pressing reason is that terrorists who organize attacks in India often do the same for attacks inside Saudi Arabia. Forced to choose, the Saudis went with joining Indian efforts to find and neutralize Islamic terrorists operating in India and Saudi Arabia.
Although India and Saudi Arabia should be the best of enemies, they have been growing closer over the last decade. While Saudi Islamic conservatives consider Hinduism (the religion of 80 percent of Indians) paganism of the worst sort, Saudi leaders take a more balanced view. India has supplied Arabia with manufactured goods and knowledge for thousands of years. Over a million Indians work in Saudi Arabia, the largest foreign contingent in the kingdom's huge expatriate workforce. India has the second largest number of Moslems of any country on the planet. Most importantly, India was quick to offer counter-terrorism help when al Qaeda turned on Saudi Arabia in 2003. Since then, the Saudis and Indians have cooperated closely to battle the Islamic terror groups that threaten them both.
All of this bothers Pakistan, also an ancient friend of Arabia. While overwhelmingly Moslem, Pakistan contains a province (Sindh) where Hinduism has its origins. Much of the ancient Indian trade with Arabia came from modern Pakistan. There is more trade with India now but Pakistan has also provided a lot of workers, though not nearly as many as India or with such a profusion of skills.
One thing that Pakistan provides, that Saudi Arabia does not like at all, is sanctuary for Islamic terrorists, including some who have carried out attacks in Saudi Arabia. When pressed by Saudi Arabia, Pakistan denies any knowledge of Saudi terrorists in Pakistan or insists that these fellows must be in the tribal territories, where government control is weak. Saudi Arabia knows better, and that's one reason the Saudis have turned to India, which has a similar problem with Pakistan.
The Saudi relationship with India took a major move forward last June 21st when Saudi Arabia first extradited an Islamic terrorists to India for the first time. This began with the arrest of a Pakistani Islamic terrorist (Sayed Zabiuddin Ansari), who was living in Saudi Arabia. This man was wanted by India for running the November 2008 terror attacks in Mumbai, India. Ansari belonged to a terrorist group that had the support and protection of the Pakistani government. Ansari believed he could stay in Saudi Arabia without any problem. But when India discovered Ansari was in Saudi Arabia, they began secret negotiations with the Saudis to have Ansari arrested and extradited to India. This happened on June 21st, and Pakistan has warned its state supported terrorists that Saudi Arabia was no longer safe. For the Saudis this provides a way to apply more pressure on Pakistan when it comes to matters (Islamic terrorists) that hurt Saudi Arabia and that Pakistan has formerly ignored.