Senior Congress leader Kapil Sibal hit out at the police over their probe into Sunday's violence in Uttar Pradesh's Lakhimpur Kheri district that left eight, including four farmers dead. "Timing is of the essence in a murder case, the investigation must be immediate; arrest has to be immediate," senior Congress leader Kapil Sibal said.on why the Murder accused in Lakhimpur Kheri violence is still at large & not been arrested.