BANGALORE, JANUARY 3 The Bangalore police on Tuesday announced their first major breakthrough in the investigations into the December 28 attack on the Indian Institute of Science by showing the arrest of a 35-year-old resident of Nalgonda district in Andhra Pradesh, Abdul Rehman alias Umed alias Mohammed Raiz-ur Rehman— reportedly the head of the south India operations of the Lashkar-e-Toiba.

Rehman was picked up in Nalgonda on January 1, Bangalore Police Commissioner Ajay Kumar Singh said without elaborating on Rehman’s role in the December 28 attack that killed former IIT Delhi professor M C Puri.

Sources said that the arrest has been made on the premise that Rehman funded and masterminded the IISc attack. Rehman’s passport shows that he has been in Saudi Arabia for nearly 13 years. The passport also bears immigration stamps for Bangladesh, sources said.

‘‘He has been in India since Ramzan. The passport is stamped for entry at the Hyderabad airport on October 15, 2005, for his arrival from Riyadh,’’ sources revealed.

During his interrogation over the past few days, Rehman has said that he has never visited Bangalore. He claims to have only visited Hyderabad and Chennai on one occasion.

According to sources, Rehman is a follower of the Al Haddees sect in Islam and was a sort of preacher and a translator from Arabic to Urdu at an Islamic Study Centre in Saudi Arabia. Police are trying to follow up on leads on friends and contacts of Rehman found at his Nalgonda residence.

‘‘We don’t think he was the perpetrator of the attack. His arrest is in relation to the conspiracy. He amassed a lot of wealth in Saudi Arabia and was funding organizations involved in proselytizing for Islam in India. There are discrepancies in what he is telling us,’’ a senior police official said.