If the police are not executing a Non-Bailable Warrant (NBW) issued in your cheque bounce case, you cannot file an FIR against them for failing to do their duty. Instead, you can write to senior police officials like the OC and SP about the unreasonable delay. You can also inform the court of the delay and provide any information you have about the accused's whereabouts. Your lawyer can also file an application for early disposal of the case.