So Gunn, for instance, could have just kept on walking and the office shouldn't go after him without probable cause. I guess the big question is what would constitute probable cause
To conduct a Terry stop he needs reasonable suspicion. Being out at 3am by itself is not going to fill that. If you combine that with the alleged burglaries in the neighborhood then it's possible. I would have to know what he saw or said as to why he approached him to form an opinion. If he can articulate a Terry stop then the man would be detained until he satisfied his suspicion. That detention should be brief. They cant hold someone an infinite amount of time.