After arresting one person, theArunachal Pradesh police has claimed to have cracked the IRBn constable murder case in West Siang district.The murder weapon, a 12 bore SBBL gun, along with one live cartridge were seized from him, the police said on Wednesday.The India Reserve Battalion (IRBn) constable, Tapop Yajo, was shot dead in the early hours of March 3 when he was on duty at the Chief Judicial Magistrate's (CJM's) Court at Aalo, the headquarters of West Siang district.The accused was arrested on Monday. The 24-year-old man is a resident of hails from Bingung village in Siang district, the Superintendent of Police (SP) of West Siang district, Jummar Basar, said.A police team lead by Deputy SP Sange Thinley, who was appointed as the investigating officer in the case, arrested the accused and produced him before the court, where he had admitted committing the crime, the SP said.The accused was remanded to judicial custody, he said, adding, the vehicle used in committing the crime was also seized.The incident had created a sensation across the state and evoked condemnations from all quarters in media and social sites.Meanwhile, the Speaker of Arunachal Assembly, Pasang Dorjee Sona, lauded the West Siang Police for cracking the case within six days."The people of the entire state, particularly the members of the deceased's family, have been patiently waiting for the arrest of the perpetrator," the Speaker said.The planned and quick action by the district police has yielded result, Sona said.