Alleged terror suspect Fasih Mehmood, left, was deported to India on Monday, and the Delhi police has taken him into its custody.
India had been pushing for Mehmood's deportation for the past six months, but required much coaxing before the Saudi Arabia government was convinced about the Indian request.
Mehmood, 28, an engineer, was working in Jubail, Saudi Arabia, before his name allegedly cropped up in cases related to terrorism.
His name first appeared during the investigation into the 2010 blast at Bengaluru's Chinnaswamy stadium.
It was during the interrogation of Kafeel Akhtar -- an accused in the case -- that Mehmood was first mentioned. The police claim there are call records to show that the two men were in touch with each other.
Mehmood's name gained importance for Indian law enforcement after they discovered the engineer had his roots in Darbhanga, Bihar which, the Intelligence Bureau claims, is the new headquarters for the Indian Mujahideen terror group.
Although Mehmood was not in India at the time of the Chinnaswamy stadium blast, the police suspect he may have assisted the IM with money.
The police will also investigate if he has any connections with the IM's modules in the United Arab Emirates. Investigators will also probe if he has been in contact with IM leaders Riyaz and Yasin Bhatkal.
Mehmood is said to have completed his education in Bhatkal, Karnataka, and may have come into contact with some IM operatives there, the police suspect.
India currently shares a good relationship with Saudi Arabia, the Saudi government is extremely particular that all details are furnished before any deportation takes place.
The Saudi authorities were ready to deport Mehmood a couple of months ago. However, they sought more evidence before the process was completed.
The Saudi authorities picked up Mehmood some months ago after a request was made by the Indian government. Mehmood's family first drew the media's attention to the fact that he had gone missing. They approached the Supreme Court and sought to know his whereabouts through a habeas corpus petition.
The Indian agencies told the apex court they were working out the formalities for Mehmood's deportation from Saudi Arabia.
The family said Mehmood had disappeared on May 13 after he was taken away by a group of Arab and Indian men. The family also appealed to the Indian ministries of home and external affairs for assistance.
The government on Monday termed Mehmood's arrest as a 'very important catch,' saying Saudi Arabia had fully cooperated in his deportation to India.
Union Home Secretary R K Singh said India had submitted 'material evidence' against Mehmood to Saudi Arabia to press its demand for his deportation for alleged involvement in terrorists acts in the country.
Indian officials, Singh said, also provided documents to prove Mehmood's Indian citizenship.
Saudi Arabia, Singh added, had never stated that Mehmood would not be deported, but the process took some time. Mehmood, the home secretary claimed, was the 'key facilitator' for 13 Indian Mujahideen terrorists who were arrested from Bihar, Uttar Pradesh and other locations late last year.
These IM operatives were arrested in connection with the 2010 blast at the Chinnaswamy stadium and the shootout near Delhi's Jama Masjid.