Application for a new trial shall be made by motion upon written grounds, and except for the cause of newly discovered evidence material for the person applying, which he could not with reasonable diligence have discovered and produced at the trial, shall be filed within three days after the verdict was rendered, or the decision of the court where a trial by jury has been waived, unless it is made to appear by clear and convincing proof that the defendant was unavoidably prevented from filing his motion for new trial in which case it shall be filed within three days from the order of the court finding that he was unavoidably prevented from filing such motion within the time provided herein.
Motions for new trial on account of newly discovered evidence shall be filed within one hundred twenty days following the day upon which the verdict was rendered, or the decision of the court where trial by jury has been waived. If it is made to appear by clear and convincing proof that the defendant was unavoidably prevented from the discovery of the evidence upon which he must rely, such motion shall be filed within three days from an order of the court finding that he was unavoidably prevented from discovering the evidence within the one hundred twenty day period.