Undead Air

Your radio show has gotten quite popular. By reporting on strange urban legends, conspiracies and scary stories, it has developed a cult following of fans, who regularly call on air to tell their delusions and stories.
On Devil's Night, a shady character calls:
"I will commit murder. One in each time zone. You will be the last victim."
Is it yet another pathological liar, or is there something more to their words?