All four persons, including state minister Sabitri Mitra's son-in-law Samadip Sarkar alias Tinku, accused of beating up Election Commission personnel in Malda's Manikchak area were arrested on Friday.
Union Minister of State for Health and Family Welfare A H Khan Chowdhury was allegedly attacked during a Congress rally at Kaliachak in West Bengal's Malda district on Tuesday.
The Trinamool Congress won 211 seats.