Five SIM cards and a mobile phone have been found on the premises of Alipore Central jail in raids on Sunday and Monday.

On Sunday, two SIM cards, wrapped in a piece of cloth, were found under a brick on the grounds of the jail.

On Monday afternoon, three more SIM cards were found wrapped in pieces of paper in the cells of two under-trials and a mobile phone was found wrapped in a sheet of cloth in a toilet.

“A probe has been ordered to find out how the SIM cards and the cellphone were smuggled into the jail. Showcause notices were slapped on two warders,” said a senior jail officer. “The mobile phone neither had a battery nor a charger. We have got in touch with the service providers to find out the call records of the SIM cards,” added the officer.

In January, six cellphones, three SIM cards, a DVD player, a knife and a pair of scissors were seized from the cells of two undertrials at the jail.

The latest haul has prompted the formation of a “special team that will take action against insiders who are hand-in-glove with the criminals”.

Another officer said the department was trying to install more jammers in the jail to prevent criminals from using cellphones on the premises.