Jamshedpur, Nov 22 (PTI) An assistant sub-inspector of police was arrested in Jamshedpur in Jharkhand on Monday for allegedly killing his girlfriend by crushing her head and then strangulating her, a senior police officer said.Dharmendra Kumar Singh, 39, who was posted at the Sakchi police station, allegedly killed Varsha Patel and dumped her body in a pond, said Subhash Chandra Jat, the superintendent of police (city).Varsha, 32, a resident of South Park, went missing on November 12 and a complaint was registered at the Bistupur police station by her sister Jaya, he said.Singh was in a relationship with Varsha for over a year, Jat said.Singh told police that she was frequently blackmailing him to extort money and also preventing him from visiting his native place in Bhojpur district of Bihar, the officer said.Fed up with the blackmailing, Singh took leave from duty and allegedly planned to kill her, he said.He took Varsha to his residence in the Telco area, and crushed Varsha"s head against a wall before he strangulated her to death, following an altercation, Jat said.Singh then stuffed her body in a plastic bag and dumped it in a pond in the Telco police station area, the SP said.He threw Varsha"s belongings into the Subarnarekha river and her mobile phone in a bush in the Bistupur area, which the police has recovered.He then left for his native village in Bihar, police said.Sanitation workers spotted the decomposed body in the pond on November 18, which was subsequently sent for post-mortem by the police, they said.Varsha"s family members identified the body by her gold bangles, chain and clothes, police said.Following a thorough investigation, some suspects were detained for questioning and based on the evidence gathered, Singh was arrested from his native village and brought here, the SP said. PTI CORR SOM SOM