What have been called “highly suspicious” VHF transmissions along the Bengal-Bangladesh border now are being considered signals of interest to India’s Intelligence Bureau. According to media accounts, after several days of monitoring, Ambarish Nag “Raju” Biswas, VU2JFA, and his team have determined that the transmissions, taking place on Amateur Radio frequencies, are coming from the area of Basirhat in West Bengal. The voice communications have been heard at night.

Federal Ministry of Communication officials in India had asked Biswas, the secretary of the West Bengal Amateur Radio Club, and his fellow hams to keep an ear on the strange VHF signals.

Biswas told Press Trust of India that he’d found the recent signals suspicious because he’d heard similar communications in 2002 and 2003. Subsequently, police arrested six “extremists,” from Gangasagar, an island in the Ganges River delta, he was quoted as saying.

An earlier article in the Hindustan Times reported that the signals were being heard in the dead of night, with participants said to be in motion and speaking in some sort of code in Bengali and Urdu with a Bangladeshi accent. They also used numerical codes, according to the report.

Indian Intelligence Bureau officials did not rule out the possibility that terror organizations were behind the signals. “The border of India-Bangladesh near West Bengal is porous,” a senior Intelligence Bureau official said in a report that appeared in The Indian Express. “Smugglers and extremists try to exploit it fully.”