Khulna: A tribunal here on Thursday convicted a man and sentenced him to life term imprisonment for killing a security guard of a private company in 2007, reports UNB. Khulna Speedy Trial Tribunal Judge MA Rab pronounced the verdict sentencing Wasiqul Sardar to life in jail along with Tk 5,000 fine and one year more jail in default of the fine payment. The tribunal also acquitted two other accused--Mohsin Reza and Bachchu Ahmed-as the allegations they faced could not be proved. According to the prosecution, Shital Sardar, 35, a security guard of a private organisation in Dakope upazila, was strangulated to death by the convict on February 20, 2007. Bidhan Sardar, brother of the victim, later filed a case in this connection. Shamsul Haq, the then officer-in-charge of Dakope Police Station and also the investigation officer of the case, submitted charge-sheet against three people in this connection.