The deceased was a schoolteacher and a CPM local committee leader.
Around 11.30 am, the armed trio entered the primary school, which is located in a remote part of the village.
They dragged Singh out of the class and opened fire once outside the school premises.
The miscreants also smashed his face with a heavy stone and fled.
West Midnapore Superintendent of Police Rajshekharan said no one has been arrested yet.
Police are conducting a thorough search in the area.
But CPM district committee secretary Dipak Sarkar claimed that Singh was killed by a Maoist outfit active in the forests in the district.
The SP did not confirm whether a Maoist hand was behind the incident.