When the testimony, for either the government or the defendant, of a material witness who is in custody within the Virgin Islands is desired, the court in its discretion may, upon the application of either the government or the defendant, issue an order for his temporary removal from the place where he is in custody, and for his production before the court. The order may be executed by the marshal or any of his deputies, or any member of the police force, and it shall be his duty to bring such person before the court and when his presence is no longer required as a witness to deliver such person back to the officer from whose custody the witness was received.