Section 1145(2)(f) in Police Regulations, Bengal , 1943
(f)When a servant of the Crown who has furnished security takes leave or is deputed to other duty for more than six months, he should ordinarily be required to stand surety for the servant of the Crown appointed to act for him to the extent of his own security or for the difference between the security offered by the acting incumbent and that prescribed for the appointment. If, however, in special circumstances the permanent incumbent is unable to do so, the servant of the Crown acting for him must furnish the full amount of the security, or, at the discretion of the head of the office, half the amount in cash and the rest in fidelity bonds. Security to the full amount should always be. taken when the acting appointment is made for more than six months.