The police clarified that the men are only being questioned; no arrests have been made in the case.

Sources said the men were summoned by the police on the basis of phone calls and e-mails sent to Kafeel during the course of the latter's stay in Bangalore in December 2006.

Meanwhile, the police appears to have run into a stonewall in their questioning of Kafeel's family. Initially, the police said, his mother had confirmed that the man who drove the flaming SUV into Glasgow airport and who is currently battling for his life in a hospital with 90 per cent burns, is Kafeel, but now the family has changed its stand.

The police say it is becoming increasingly difficult to extract any information from the family who remain tight-lipped most of the time.

There are also conflicting reports about the hard disk seized from Kafeel's home last week and sent to C-DAC in Kerala [Images] for deciphering. The police claim apart from 'jihadi' videos, they also found a video explaining how syringe bombs work on the hard disk.

Sources said Kafeel may have deleted material from the hard disk. An expert team from Thiruvananthapuram has now brought the hard disk back to Bangalore and is trying to extract as much information possible from it along with the local cyber crimes cell. The sources claim that even if Kafeel had deleted information, this team could retrieve most of it by using the CyberCheck Version 3.0, a software developed by C-DAC for use in cyber forensics.

A senior police officer said the information stored on the hard disk is vital to the investigation as they believe it also contained several names with their contact details and e-mail ids.