Lucknow, Aug 9 (IANS): The Lucknow police and the cyber cell have tracked down a 22-year-old student and his 13-year-old brother who had been posting lewd remarks in a WhatsApp study group of a local college.

Additional Deputy Commissioner of Police (ADCP), North, Prachi Singh, said, "The boys were using an application to change the landline number to a foreign origin mobile number to make tracking difficult for the police."

She said, "During investigation, we found that the accused made 13 calls on the girl's number to harass her. We also recovered the phone used by them and it was verified by the cyber cell on the basis of the surveillance that showed that the phone was present at the house of the accused."

Police said the 13-year-old younger brother of the main accused was a classmate of the girl.

The ADCP further said, "Laxity on the part of college administration also surfaced during the probe. Police said some students were made WhatsApp group admin and they added some outsiders to the group. Therefore, it became difficult to trace the link to an outsider."

Additional Commissioner of Police (ACP), cyber cell, Vivek Ranjan Rai said that the minor boy had tried to harass the girl because she had stopped talking to him and was not friendly anymore.

"He felt alienated as she was her only friend and had suddenly stopped talking to him," the ACP said.

The girl's mother had lodged a case on July 17 after which the police started investigations.

Cops were initially baffled as the mobile number used to send messages was of foreign origin.

ACP, Aliganj, Akhilesh Singh said while the minor was sent to juvenile home, his elder brother was arrested on Sunday.