¶1The defendant appeals his conviction for burglary. Held:
¶21. The evidence was sufficient to enable a rational trier of fact to find the defendant guilty beyond a reasonable doubt. See generally Crawford v. State, 245 Ga. 89 (1) (263 SE2d 131) (1980).
¶32. The trial court did not abuse its discretion in allowing the defendant’s confession into evidence. The testimony presented by the state at the Jackson v. Denno hearing amply supported the court’s conclusion that the confession was made freely and *199voluntarily after the defendant had been advised of his Miranda rights. There is no requirement that a waiver of constitutional rights be in writing. See Spain v. State, 243 Ga. 15, 16 (252 SE2d 436) (1979).
¶43. The trial court did not abuse its discretion in overruling the defendant’s motion for mistrial after a witness for the state testified that he had seen the defendant during the week of the burglary, “after he got out of trouble.” This statement did not place the defendant’s character in issue as it was unclear what “trouble” was referred to. See generally Jackson v. State, 156 Ga. App. 255, 256 (274 SE2d 665) (1980); Nicholson v. State, 158 Ga. App. 858 (1) (282 SE2d 407) (1981). Indeed, the comment apparently had reference to the defendant’s arrest for the charge on which he was being tried.
¶5Judgment affirmed.