On phone call

4 years back my husband was working with a furniture manufacturer and used to go to his factory and there one day when he stopped his taxi infront of the gate, one guy shouted at taxi guy and was beating, my husband tried to calm him and asked not to do this then that guy hit my husband in anger in head, and he shouted, so lot of people came and owner of factory too and they took that person to police station and did FIR or GD we do not remember now, After that there was nothing happened - and we shifted to Delhi after 6 month of this case, and returned back again after a year in kolkata - and till now its almost 3 and half years we here in kolkata only, and suddenly we got a call from somebody saying that police is calling and my husband need to meet him and come to police station, as there is a case pending and they have sent summon ( but till now we have not received any notice or summon or nobody has come to our place for any reason) We want to know is it possible to police to call after so many year ? what we need to do in this case ? is it genuine ? what will be our role ? Without any notice or paper why they calling us ? Is there any reason to Fear if we did GD or FIR