MUKILTEO — Robert Pennington and his father, Terry Pennington, ascended a pair of tall stepladders in place along a wall of the Electroimpact company. They fussed with ties that held a 12-foot banner proclaiming: "Free Rob Pennington." When the banner fluttered to the ground, an appreciative crowd of about 150 cheered. It was a homecoming for the 22-year-old U.S. Marine.