KMGH-TV, Denver, reported Dylan Stanley Dougherty passed a note to his sister detailing the plan. He contacted her by removing a plumbing access panel, then following the plumbing space in the ceiling to her cell.
The arrest affidavit alleges a homemade knife and letter to the FBI were found in Dougherty's cell during a Jan. 10 search. He allegedly planned to subdue guards, take their keys and escape with his sister, Lee Grace.
The two and brother Ryan were arrested about 150 miles south of Denver Aug. 10 following an eight-day crime spree that began in Florida.