Guwahati, Sep 29 : Three people have been arrested for allegedly killing a 15-year-old girl and subsequently sexually assaulting the dead body in Assam's Karimganj district, police said on Friday. The three youths aged between 25 and 27, allegedly broke into the minor's home on September 9 while her parents weren't there. Partha Pratim Das, the Superintendent of Police in Karimganj, told IANS that preliminary investigations indicated the accused, who killed the girl and afterwards raped her body, was known to the victim. "The minor was first strangled to death. Post-mortem examination found that she had also been sexually molested," he said. All three have been arrested in accordance with section 376 of the IPC after the crime was confirmed. The accused were identified as Biplab Paul, Subhra Malakar, and railway worker Rahul Das'all residents of Karimganj district. Das claimed that the men killed the girl for declining their "indecent proposal". She spurned the advances of one of the accused'Rahul Das, the police said. "The accused allegedly made an inappropriate proposal to the girl but she declined. On September 9, they forced their way into her residence," another police officer stated. According to Pratim Das, preliminary investigation showed that Rahul Das was the primary planner and that the other defendants helped him carry out the crime. "Rahul is a railway employee. It is believed that the girl knew Rahul. He is being questioned by us," he stated. In their lawsuit, the victim's family claimed that Rahul had been stalking her and threatening to kidnap and kill the entire family for a few days before the murder. Additionally, according to police, they apprehended the suspect on Wednesday night after tracing one of their cellphones whose number was discovered scrawled in the victim's notebook. "We tracked them down with the help of the phone number. Her family members disclosed a number of details," Das added. As per the police, a case has been filed under several sections of the Indian Penal Code (IPC), including sections 376 (gang-rape) and 302 (murder), as well as the provisions of the Protection of Children from Sexual Offenses (POCSO) Act. "We are looking into it, so there may be more sections added. On Friday, the accused will be produced before a court," Das added. /IANS