Detective Senior Constable Bernard Dowling said the man, in his 60s, with long blond hair and wearing a fur or wool-lined cloak, had dropped burning material – such as firelighters – into at least seven post boxes in the past month.
The most recent incidents occurred twice on the one night at the post box on the corner of Lindrum Rd and Hampden Av, Friday 1 September.
No letters were burnt because the mail had already been collected. Other incidents have been in Beach St and Heatherhill Rd.
The man drives to the post boxes and wears a blue or grey jacket each time.
