Since the guard's arrival on Monday, protests in the small section of town that had been the centre of nightly trouble have begun to subside.
The quietest night was overnight Wednesday, when police arrested a handful of people in the protest zone.
Missouri Governor Jay Nixon ordered the guard to withdraw, saying: "The last two nights have been really good. I feel we're making progress."
But he noted that a state of emergency remained in effect in Ferguson.
About 100 people gathered on Thursday night, walking in laps near the spot where Michael Brown was shot. Some were in organised groups, such as clergy members.
More signs reflected calls by protesters to remove the white prosecutor from the case but Bob McCulloch said he had no intention of withdrawing.