Around 5,000 SIM (subscriber identity module) cards of different telecom operators have been found in a pond in Khetlal upazila in northern district of Joypurhat.
A sack full of papers, which locals suspect could be documents used against the SIM cards, has also been recovered from the pond.
Criminals or some extremist groups might have left the SIM cards, all of which are active, in the pond to avoid phone tracking, Hamidul Alam, superintendent of Joypurhat police, told The Daly Star.
Some local children noticed this in the morning when they went to collect vegetable, our correspondent reports quoting witnesses.
Rizvi, 7, son of one Abu Musa of Ziapur village, went to a nearby pond around 7:30am when he first found a SIM.
Curious, he searched for more and got around 50 to 60 SIM cards from near the bank of the pond.
Later, his parents joined him and recovered more SIM cards.
On information, other villagers rushed there and joined the search for SIM cards, our correspondent added.
In total, the villagers recovered around 5,000 SIM cards of different mobile phone operators from the pond.
The recovered SIM cards are mostly of Airtel and Banglalink mobile phone operators, said our correspondent quoting the villagers.