The probe into Tuesday’s terror mail has drawn a blank and cops are now banking on retrieving data from the hard disks seized from the Salt Lake cyber cafe owned by prime suspect Kaushik Basu.

Sleuths are waiting for the report of the Central Forensic Science Laboratory (CFSL), where the hard disks and Central Processing Units (CPU) of seven computers were sent. “The data stored on the hard disks are important. Since the records were deleted from all seven computers by the time officers raided the cyber cafe in IA block, we need the help of CFSL experts,” said Jawed Shamim, the deputy commissioner of police, detective department.

The sleuths admitted to some lapses on their part. According to an officer, the keyboards should have been sent for fingerprinting immediately after the cafe was raided.

“If we had identified the real culprit, we could have matched his prints with those on the keyboards,” said an officer.

Basu was arrested hours after the hoax mail was sent on Tuesday night. The next day, Sabitri Dandapat, the domestic help of the Basu family who helped Kaushik run the cafe, was arrested.

The police are, however, yet to locate the three men who Kaushik and Sabitri say were in the cafe around the time the mail was sent.

Detective department sources told Metro that one of Kaushik’s friends was picked up for questioning on Thursday but was released later.

The police have prepared sketches of two unidentified men based on Sabitri’s statements, but they weren’t satisfactory. “The sketches were not up to the mark. Our artists are drawing fresh portraits of the duo,” said the officer.

On Friday, Kaushik’s wife Malini met him at the Lalbazar central lock-up. “He cannot take so much pressure… I am miserable,” she sobbed.

“Kaushik is innocent. He doesn’t even know how to take care of our baby. My father-in-law and I looked after her while Kaushik would remain engrossed in his studies,” she said.