These recoveries were also made last month during a surprise check by authorities.

“It is not clear yet who was using the Internet and for how long. The data cards and pen drives were smuggled into the jail by outsiders who came to meet the prisoners. It is a serious matter because terrorists and criminals might have been using the data cards to connect with their counterparts and a lot of information related to Tihar might have leaked out,” a source said.

Three pen drives were reportedly recovered from Jail no. 2, 3 and 4 along with a few data cards in June. “These pen drives were recovered from the computer rooms and the compound of the educational area of the jails. When we checked the computers, we found that the Internet had been accessed using data cards,” the source said.

High profile prisoners and terrorists are lodged inside these three jails and the authorities did not disclose the identities of those using the Internet and pen drives.

The pen drives recovered contained pornographic movies that were allegedly watched by prisoners on computers installed by Tihar Jail. Tihar has computers in each jail for computer education of prisoners. “We are checking CCTV footage to ascertain who all used these cards. Experts are working on whether any emails were sent out,” the source said.

When contacted, Tihar Jail Law Officer Sunil Gupta and Director General B K Gupta refused to comment on the recoveries.

Sources said authorities keep recovering mobile phones from the jail. “This is scandalous because the Internet was never used inside the jail before. Any information could have been leaked or terrorists might have contacted their counterparts,” an official said.

Officials said mulaqaatis, who come to meet prisoners, bring small things for them. “We have alerted security officials at the gates and have asked them to check every person properly; superintendents have also been alerted on this,” the official said.