Patna, July 22: Riyazul Khan, the suspected Huji member arrested from Kishanganj last week, had made frequent calls to a Mumbai resident on July 13, the day serial blasts rocked the commercial capital of the country. The total duration of his calls was around two hours.

Sources in the Intelligence Bureau said Khan, also known as Akash Sheikh alias Sarkar, talked to the Mumbai resident for about 111 minutes on July 13 from his cellphone (9196365793).

He had also made calls to Bangalore the same day. The conversation continued for hours together, a top police officer associated with the investigation said.

Sources said Riyazul had made frequent calls to Patna, Kerala and Calcutta between July 11 and 13, hinting at his suspicious activities.

“The officials are now trying to ascertain the identity of the person who Riyazul had talked to on the day of the serial explosions in Mumbai,” the investigating officer said.

The investigating officials have obtained the call details of his three other cellphones (09771899740, 8101116425 and 9973934984) recovered from his possession during a raid on the house of Mehtab Alam at Maheshpur under Pauwakhali police station on July 16.

The officers are trying to recover Riyazul’s laptop that was reportedly stolen from Payal Hotel at Siliguri.

Sources said Riyazul had stayed at the hotel for a few days before he took Mehtab’ s room on rent for Rs 500 a month.

“The laptop would probably give some vital clue about his links with terrorist outfits, if any,” an investigating officer said.

Riyazul’s account with the State Bank of India is also under the scanner of the investigating agency. The officials have come to know about withdrawal of huge money through an ATM card of the Central Bank of India.

The investigating officer said Riyazul had a separate account in the Standard Chartered Bank.

“We have recovered some documents related to transactions of money from his different bank accounts,” he said, adding that a bunch of keys was also seized from him.

Kishanganj superintendent of police Ranjeet Kumar Mishra refused to divulge any information in the case.

“It will not be justified to disclose anything at this juncture. The investigation is still going on,” he told The Telegraph over phone on Friday.

Sources said the police had not yet submitted any petition to the court to take Riyazul on remand for further interrogation. “We will take him on remand when required,” an officer posted at Pauwakhali police station said.

Both Riyazul and Mehtab, who have been booked under Foreigners Act and different sections of the Indian Penal Code, are at present lodged in Kishanganj jail. The sleuths had interrogated Riyazul for several hours before he was forwarded to jail.