A man was arrested by the crime branch for allegedly duping over 700 people to the tune of Rs 7.21 crore, police said.Jai Prakash Saini cheated people on the pretext of giving membership of flats in a co-operative society in Bakhtawar Pur area here.He ran away after collecting money from the people three years ago and was declared a proclaimed offender by a court, the police said.Saini was wanted in five cases of cheating amounting to Rs 7.21 crore and was living in Kolkata with a false identity.