Last night, what members of Occupy Los Angeles intended as a colorful exercise of their rights during the monthly Art Walk in Downtown turned violent and ugly as the Los Angeles Police Department handled the "protest" with a show of force.

Riffing on a current movement of people using sidewalk chalk messaging and drawing as a form of protest, the Occupiers made clear their intent this week that they would be out and about in the city's center making their presence known. They called the event "Chalk Walk" and used social media to promote it.

From an Occupy L.A. release dated July 10: "The Occupiers plan to chalk up downtown, in front of City Hall, Police Headquarter[s], and other spots around downtown, in exercise and enjoyment of their Rights. [...] Occupy LA's plan is to widely disseminate chalk at this Thursday’s Downtown Artwalk and video the project and to get local media to cover their efforts."

What they got in return was the LAPD in riot gear, and a tense night that involved Art Walk goers and bystanders, injuries, and arrest.

Though there had been a noted heavy police presence in the vicinity of Art Walk, what's being described as the "melee" by the media broke out at around 8:40 p.m. The LAPD soon went on tactical alert, which means all officers on duty city-wide must remain on duty until further notice.

LAPD on Citywide tactical alert due to Occupy-related protest downtown. — @LAScanner (@LAScanner) July 13, 2012

Patrons, residents, and chalking Occupiers were confronted with LAPD officers in riot gear. A total of 140 officers were deployed in the area, said Officer Norma Eisenman of the LAPD's Media Relations section, according to City News Service.

While it seemed confounding that the LAPD would have such a strong reaction to a "chalking" event, the LAPD says they were reacting because violence had broken out, and it was directed at them.

Lapd says issue isn't w chalk but rocks and botttles thrown at officers #dtla #artwalk — Richard Winton (@LAcrimes) July 13, 2012

"Four officers were hurt and treated for minor injuries in the Thursday night incidents. One officer suffered a minor concussion after being hit in the head by an object thrown by the crowd, police sources said," according to the L.A. Times.

People in the area report being herded from sidewalk to street and back to the sidewalk, then chastised for not dispersing.

From the post-event release issued by Occupy L.A.'s media team:

“The police provoked us,” said an unnamed Occupier, “I was pushed by cops into a garbage can, a parked car, and eventually into the street, where I was ordered back onto the crowded sidewalk I had just been pushed from.”

At least two people were shot with “stinger balls”. One young man was shot in the chest and bleeding from the impact. Another guy was shot in the face. “The LAPD shot indiscriminately into the crowd at close range,” said another witness said, “I was trying to talk to the media and as we were talking a projectile was shot in between us”.

Many people on scene, including members of the "Chalk Walk" Occupy group, have said they felt the LAPD used excessive force to control the crowd and handle the protest. Again, from the Occupy L.A. post-event media release:

Officer Karen Rayner of LAPD media relations said she did not have specific information on crowd control tactics used Thursday other than skirmish lines.

Ultimately the tactical alert was reduced to the Central Station area, however by that time, several arrests had been made and injuries reported.

The L.A. Times tallies 19 arrests, and summarizes the reasons as follows:

Officials said nine of those arrested were booked on vandalism charges, three were booked for assault with a deadly weapon on a police officer, two for failure to disperse, two for resisting arrest, two for blocking traffic and one for attempted assault with a deadly weapon on a police officer.

In the aftermath, the Occupiers assert they remain the target of the LAPD, but that their only action during Art Walk was to engage in chalk writing on the sidewalks (and in the rain, no less, making short tenure for some of the messages).