(NEWSER) – An FBI agent today laid out the meticulous detail used by James Holmes to booby-trap his apartment on the night of the Dark Knight massacre in Aurora, Colorado, reports USA Today. According to his plan, a boombox would start blaring in the empty apartment at midnight. When neighbors or police knocked on his door, that would jostle a fishing line and set things in motion, as the Denver Post explains:

• "The line would topple the thermos full of glycerin, and the glycerin would mix in the frying pan with the potassium permanganate to create a flame. The flame would set the petroleum-soaked carpet on fire. The fire would light the fuses. The fuses would detonate the jars filled with homemade thermite, smokeless powder and stove-top napalm mixed with bullets."

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