There were high hopes that the nightly protests in Ferguson would end peacefully for a change Tuesday. That promise held out for most of the evening - until a water bottle flew at police.
By that time, most protesters had cleared out. Journalists outnumbered those who remained.
Officers put on helmets and shields, lined up on in front of some businesses and demanded a small crowd there clear out.
But when the bottle flew, officers broke into a sprint, chasing after young men.
This prompted a handful of agitated protesters to toss more bottles, glass and plastic.
At least 31 people were arrested in Ferguson after peaceful protests devolved into another night of chaos. And many of those arrested came from as far away as New York and California, said Missouri State Highway Patrol Capt. Ron Johnson early Tuesday.
Johnson didn't provide additional details, but his remark confirmed what many in Ferguson have been saying all along: the protesters who have turned the nightly demonstrations into tense confrontations with heavily armed police officers aren't local residents.
"I'm telling you, we're going to make this neighborhood whole," Johnson said. "And I am not going to let criminals that have come out here from across this country or live in this community define this neighborhood and define what we're going to do to make it right."
He has a Herculean task ahead of him.
Chosen by the Gov. Jay Nixon to head up security operation - after Ferguson police was roundly criticized for its heavy-handed approach - Johnson was welcomed last week.
But those sentiments have soured as security forces under his command lob tear gas and stun grenades at rowdy protesters who toss rocks and Molotov cocktails at them.
CNN's Jake Tapper echoed the frustrations of many in the crowd after the latest encounter Monday night.
"Absolutely there have been looters, absolutely over the last nine days there has been violence, but there is nothing going on in this street right now that merits this scene out of Bagram. Nothing.
"So if people wonder why the people of Ferguson, Missouri, are so upset, this is part of the reason. What is this? This doesn't make any sense."
See more on this developing story on CNN.com