When a letter containing foreign substance is sent through the detector, it emits high beep sound and glowing light, say BDDS personnel.

The Bomb Detection and Disposal Squad (BDDS) of the City Police has been equipped with a new Letter Bomb Metal Detector for detecting explosive substances concealed in letters.

Working on magnetic induction principle, the anti-sabotage equipment in the size of a small box also functions on battery fitted inside the kit.

When a letter containing foreign substance is sent through the detector, it emits high beep sound and glowing light, say BDDS personnel.

The Security Branch CID of the State Police has dispatched such detectors to many districts and police Commissionerates, a senior official here said adding that the indigenously manufactured gadget was a replacement to the one sent earlier.

The services of BDDS are sought for bomb detection and disposal missions in the central zone encompassing Tiruchi, Pudukottai, Perambalur, Karur, Ariyalur, Thanjavur, Tiruvarur, and Nagapattinam districts.

Already equipped with kits used for anti-sabotage missions including deep search metal detector, multi-zone metal detector, x-ray scanner and handheld metal detectors, the BDDS would soon be provided with three explosive vapour detectors and a non-linear junction detector as a replacement for older gadgets, official said.

Also comprising ex-military personnel with experience in anti-sabotage missions, the BDDS had carried out 10 bomb disposal missions at different places across the zone including Tiruchi, Kumbakonam, Karur, and Tiruvarur in 2012. It had carried out nine bomb disposal missions in 2011.