Eight mobile phones were seized from inmates of Faridkot Central Jail on Friday, a day after National Investigation Agency seized Rs 39.60 lakh from the house of jailed gangster Harsimrandeep, alias Sema Behbal. The seizure of cash from his house has lent credence to the theory that many gangsters are continuing their criminal activities and extortion business from the prison using cellphones, said a police officer.