PATNA, Jan. 5 -- Police in Banka district of Bihar on Saturday arrested a professional lawyer and his son for allegedly killing his 17-year-old daughter over suspecting that she was having an affair with a "low caste" youth of the neighbourhood. The girl's throat was slit, police said. The incident occurred in Chamreili village of Banka district. The minor was reportedly missing from January 2. The lawyer Shashibhusan Jha, according to police, tried to make the murder appear a case of kidnapping by filing an FIR against the neighbouring youth named Shailesh Kumar. In his FIR, the lawyer had alleged that Shailesh had kidnapped his daughter with the intention of marriage. Following this, Banka SP Upendra Nath Verma constituted a Special Investigation Team (SIT) under the leadership of DSP Amar Viswas to probe the disappearance of the girl. A Forensic Science Laboratory (FSL) team was also roped in to assist in the investigation. The FSL unit found blood stains inside the deceased's house. It hinted that the girl was murdered in her room at her house. According to officials attached with the probe team, the accused had used the bedsheet, clothes and other items to remove the bloodstains and all these were recovered by the investigating team. Victim's blood stains were also found on the Raksha Sutra (Kalawa) tied on the lawyer's hand, which became the most solid scientific evidence of his involvement. Police also recovered the knife which was used in the murder hidden in the courtyard. The SIT also collected call details of the accused's phone and technical details that suggested that he was the culprit, an official said. Police investigation revealed that on the night of January 1, the minor had an argument with her father and was adamant to marry her 'boyfriend' Shailesh who was said to be from a "lower caste". The father was against the union as he feared "social stigma" and when the girl didn't budge, he killed her by slitting her throat with a sharp weapon, said an official who was part of the probe team. He added that after the murder, the lawyer threw the body in a canal 250 metres away from the house. On Saturday, her blood-soaked body was recovered by police from a canal on the outskirt of the village. Shailesh Kumar, the girl's boyfriend who was a suspect and a named accused in the FIR filed by father, proved to be an important witness for the police. "Shailesh shared with the police that he was talking to her on the phone at around 10:30pm on the night of the incident. During the conversation with him, the girl feared that her life was in danger. While Shailesh was still in conversation with her, her screams were heard and suddenly the call was disconnected," said Banka SP, adding that this conversation is pivotal evidence against the accused father....