One person was killed and at least eight injured in a clash between activists of the ruling Trinamool Congress and the CPI-M in West Bengal's West Midnapore district, police said on Thursday.The clash took place on Wednesday night following an argument over digging a pond in Kharagpur in the district."There was a long standing dispute over the digging of a pond at Budra village. Last night, there was a clash between the rival parties, resulting in the death of a man while eight others were injured," said a police officer, adding that no arrest has been made so far.The man who was killed has been identified as Prabodh Patra, a Trinamool activist."It is a well planned murder. CPI-M goons have been hatching a conspiracy for long and last night, they attacked Patra with axe and swords and killed him," said Dinesh Maiti, a local Trinamool leader