A man arrested on Saturday (July 6) at Taylor Swift's show in Pittsburgh will undergo a mental evaluation after police say he made death threats against the singer and held up a sign reading "Taylor is with Satan." The poster was one of several Joseph Jackson was holding when police nabbed him at Heinz Field.

Prior to the show, Jackson allegedly made death threats against the singer on Facebook. "Taylor Swift must perish and die," one read, according to KDKA in Pittsburgh. Another sign he had said "I luv you Taylor." When police detained him, he became agitated when asked about the death threats.

“Taylor Swift is Satan and that 6,000 years is six days and death comes on the sixth day, so Taylor Swift is in danger," he explained, according to the CBS affiliate.

The 28-year-old from Clarksburg, Pa. is being held in the Allegheny County Jail on trespassing and resisting arrest charges. He won't have a court date until he undergoes a complete mental evaluation. The 'Red' singer's security pointed Jackson out to local police after monitoring his comments on Facebook. They are said to be very proactive in these types of cases.