Three Trinamool Congress activists were shot dead in South 24-Parganas district on Thursday evening when gunmen attacked the vehicle of a party MLA, police said.
Motorbike borne assailants attacked the three persons when they, including the driver of the vehicle, were at a petrol pump in Joynagar area.
The incident occurred shortly after Biswanath Das, the MLA, disembarked from the vehicle at a party office nearby.
The police started an investigation into the killing detained a few people for questioning.