ARMADA (WWJ) – Was it a threat or just a joke? A tweet saying he wanted to shoot fellow workers at an Armada Subway shop has landed an 18-year-old in big trouble with the law.

Alex Rosario.

Alex Rosario.

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Alex Rosario is being held in jail on $500,000 bond on charges of domestic terrorism.

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Police say the tweet made Rosario’s co-workers nervous.

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The Riley Township man is facing 20 years in prison.