A sub-inspector of police attached to Kasimedu police station has been arrested under POCSO Act for allegedly harassing the 15-year-old daughter of his mistress, in Madhavaram, police sources said here.

The arrested SI has been identified as Sathish Kumar, 37. Police sources said that the arrest came after the series of sexual exploitation by the policeman was exposed by a Tamil publication, based on a version given by the girl's father.

Sources said that the SI Sathish Kumar, a resident of Thiruvallur district had been working in Madhavaram earlier and had initially developed intimacy with the girl's mother, 38. Later he started having an affair with the elder sister of the girl's mother.

Sathish Kumar who got attracted to the 15-year-old girl , managed to convince her mother and aunt, to force the girl to agree for his sexual advances. He started showering the girl with costly gifts including I phone and when his tactics failed he started threatening her with his service gun.

The policeman had threatened to kill her, her father, and her brother if she dares to tell the sleazy details to her father.

The girl's father when came to know about the activities tried to lodge a complaint with a local station, but he was chased away. Only then he approached the Tamil magazine, which published his version.

City police on Friday confirmed the arrest of SI, his mistress, and her sister. Apart from Pocso Act, police has also registered case under IPC section 506 (criminal intimidation ) against the suspects.