WASHINGTON — He strutted around a hotel room with an automatic weapon and a vest, watching himself in the mirror as he practiced how to pull the trigger and detonate the suicide bomb by calling a cellphone number.

He discussed hitting military targets near the Pentagon or a restaurant during the crowded lunch hour in Washington, D.C. He eventually settled on the Capitol, planning to shoot his way inside and detonate the bomb. He reportedly told undercover FBI agents that he "would be happy killing 30 people."

That's how federal authorities say a 29-year-old Moroccan man prepared for Friday, when they say he was arrested as he walked through a parking garage two blocks from the Capitol. Before the arrest, authorities say, he "took possession" of a MAC-10 automatic weapon and strapped on a vest containing what he believed to be a functioning bomb, but that both had been rendered inoperable.