Is that a pistol in your pocket, or are you just happy to see me?
Ironic that the sign directly in front of his face reads “keep right”.
So that leaves....
From behind, grasp the bottom hem of his jacket on each side in each hand, and pull it swiftly and firmly upward to temporarily entangle the head and arms; essentially creating an impromptu sack out of the subject’s own garment. Whatever is in the pockets is now captured, as the target mentally shifts gears then struggles to right the disposition of the garment. BEST OUTCOME is to get the entire hem gathered into one hand above the head, and secure it with a zip-tie before the subject can successfully react to counter or evade. Two-on-one substantially improves the odds of success, as the second can harass the target while the first secures the garment in the desired position. Oddly old school tickling is enormously effective on most subjects.
Application of spray paint or permanent dye (for subsequent identification) to the torso at this juncture is optional, but does promote vexing, near-future “WTF is THAT!?” inquiries from roommates, spouses, siblings, parents, etc.