Tā shì gè guòlùrén, hé zhè jiàn shì méiyǒu guānxi.
He was just a passerby and had nothing to do with the matter.
Tips
usage
过路 can function as a verb ('to pass by') or as an attributive adjective modifying a noun (过路人 = 'passerby', 过路车 = 'passing vehicle', 过路费 = 'toll'). It implies transience, just passing through without staying.
