Kolkata: An alleged extramarital affair led to an attack on three family members at their Bamanghata home near Anandapur early on Wednesday. Police said Akash Mondal allegedly entered Ashis Mondal’s house and assaulted Ashis, his brother Kaushik and mother Pratima, using a knife and issuing threats. Police suspect Ashis’s wife, Koyel, helped Akash plan the attack. Following a court directive, Kolkata Leather Complex police registered a case against both accused on Thursday.