(1) Even though the defendant pleaded guilty to a crime and admitted an aggravating factor pursuant to a plea agreement, the trial judge still was required to find that an aggravating factor existed and that an aggravated sentence was appropriate. Failure to do so rendered the sentence invalid. (2) Where, as a here, the use of a deadly weapon was necessary to prove the unlawful killing element of the pleaded-to offense of voluntary manslaughter, use of a deadly weapon could not also be used as an aggravating factor.