¶1 Defendant first assigns error to the trial court’s finding that he had a prior conviction, arguing that the prosecutor’s oral representations were insufficient to prove this. The standard of proof required in order to find factors in aggravation or mitigation is preponderance of the evidence. N.C. Gen. Stat. § 15A-1340.4(a) (1988). A prosecutor’s mere unsworn assertion that an aggravating factor exists is insufficient proof for the trial court to find it. State v. Swimm, 316 N.C. 24, 340 S.E. 2d 65 (1986); State v. Frazier, 80 N.C. App. 547, 342 S.E. 2d 534 (1986); see also State v. Mack, 87 N.C. App. 24, 359 S.E. 2d 485 (1987), disc. rev. denied, 321 N.C. 477, 364 S.E. 2d 663 (1988).
¶2 The State asserts that the prosecutor did not simply recite the prior convictions from memory, but read them at the sentencing hearing directly from the original court files. In a supplement to the record filed in this appeal, the district attorney has filed an affidavit stating that when he presented defendant’s record of prior convictions, he was reading from the official records of the Clerk of Court of Northampton County and that the original records were present and available in the courtroom. He neither offered those records into evidence nor sought the defendant’s stipulation as to what those records would show. See N.C. Gen. Stat. § 15A-1340.4(e).
¶3 Defendant’s failure to object to the prosecutor’s statement at the sentencing hearing, furthermore, was not fatal; error based on the insufficiency of evidence as a matter of law can be reviewed absent an objection. N.C. Gen. Stat. § 15A-1446(d)(5) (1988); see also State v. Mack, supra.
¶4*754 While we recognize that upon resentencing, it is probable that this factor in aggravation will be properly established and considered, we must apply the law consistently and conclude that we are required to provide defendant with a new sentencing hearing. The trial court erred in finding the existence of the prior conviction based solely on the prosecutor’s unsworn statement.
¶5 For the reasons stated, we vacate the sentence and remand for a new sentencing hearing.
¶6 Because of our disposition of this issue we do not consider defendant’s other assignment of error.
¶7 Sentence vacated and remanded for resentencing.