Alexis Debat contributed to this report.

Abdul Rauf, the father of the alleged London plot ringleader Rashid Rauf, is in custody in Pakistan, according to intelligence sources there.

Abdul Rauf was arrested two weeks ago in Mirpur city, in a Pakistan-controlled region of Kashmir.

Abdul's son is Rashid Rauf, whose arrest last Wednesday in Pakistan, prompted British authorities to round up 24 suspected plotters in Britain, including Rashid's brother Tayib. Rashid Rauf told police he was in the cosmetics business, and $4000 was seized from his home along with a laptop computer.

Officials tell ABC News that there is a connection between the Raufs and the family of the founder of a Pakistan-based extremist organization that is known to have ties to al Qaeda. Rashid's sister-in-law is married to the brother of Massood Azhar, the main suspect in an assassination attempt on Pakistani President Pervez Musharraf and who is wanted for a string of terrorist acts in India, including the deadly parliament attack in December 2001. Azhar is the founder of Jaish-e-Mohammad (Army of Mohammad), a group that has often acted as a facilitator for al Qaeda, according to analysts. 

British authorities are negotiating with Pakistan about the possibility of extraditing Rashid Rauf to the U.K., but the two countries have no formal extradition treaty. If Rauf is not extradited legally, any future prosecutions in the U.K. could be at risk.

Eight people so far have been arrested in Pakistan in connection with the case. Meanwhile, authorities in Pakistan continue to insist that the London terror plot was hatched in neighboring Afghanistan.